Y2 LCRS Head, Neck and Spine

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Cranial base skull picture

- acoustic - means to do with vestibulocochlear nerve (balance and hearing) - jugular - where venous system drains out of neck

Dural venous sinuses

- all of main spaces filled with venous blood --> sinuses --> jugular veins - superior sagittal sinus, then goes into inferior sagittal sinus. all of these receive cerebral veins

Prolapsed intervertebral discs

- annulus collagen at outside is ruptured and inner contents emerge --> into space where nerves. get pain and parasthesia. as go further down spine, more weight bearing --> hence vertebral bodies larger but more disc prolapses occur.

Afferent innervation of mouth and pharynx

- anterior 2/3 - sensation is trigeminal nerve (lingual nerve) (all taste goes back to nucleus solitarius in brainstem) ; but taste is from facial nerve (chorda tympani) - posterior 1/3 - sensation and taste from glossopharyngeal; also little innervation at back from vagus nerve

Nerves and vessels in posterior triangle

- anterior rami of phrenic - vagus nerve enclosed in carotid sheath, surrounds internal jugular vein and carotid artery - brachial plexus trunks into axilla and upper limbs (c5-c8;t1) - between middle scalene and anterior scalene is where some nerves emerge from - cannulae used to into neck as well - subclavian vein

Components of Vertebrae

- body- carries the weight of the axial skeleton - arch- has 2 pedicles(little foot) and 2 laminae (layer) - vertebral foramen- hole between the vertebral body and the vertebral arch, that surrounds and protects the spinal cord. - Transverse process- muscle and ligament attachment sites - Spinous Process- Muscle and ligament attachment sites

cross section of head

- can see naso, oro and laryngopharynx

Range of motion in regions of spine

- cervical is flexible in: extension, rotation and bending sideways - thoracolumbar - bending, sideways bending

What parts of the brain sit in the fossae?

The frontal lobe sits in the anterior cranial fossa, the temporal lobe in the middle cranial fossa and the brainstem/cerebellum in the posterior cranial fossa. Note that the occipital lobes lie above the posterior cranial fossa.

Which is the main sensory nerve for posterior 1/3 of tongue?

The glossopharyngeal nerve is the main sensory nerve of the posterior 1/3 of the tongue and the oropharynx. Stimulation of it (for example, by a tongue depressor placed too far back) causes the reflex expulsive effort called "gagging". Eliciting a gag reflex is the simplest test of the nerve. Don't do it in the classroom; it is an unpleasant sensation and may also trigger retching if done clumsily.

Damage to glossopharyngeal nerve

The glossopharyngeal nerve is the main sensory nerve of the posterior 1/3 tongue. Intense stimulation of the back of the tongue can cause the gag reflex If the nerve is injured then there will be no gag reflex on the respective side

Motor nerve of the tongue

The hypoglossal nerve is the ONLY MOTOR NERVE OF THE TONGUE. The simplest test is to invite the subject to stick out (protract) his/her tongue. This involves chiefly genioglossus and also the intrinsic muscles of the tongue.

The inferior thyroid artery is a branch of what?

The inferior thyroid artery is a branch of the thyrocervical trunk and the superior thyroid artery is a branch of the external carotid.

Sutures of skull

- coronal suture behind frontal bone, joining frontal bone to the two parietal bones - sagittal suture diving two parietal bones - lambdoid suture at back between parietal and occipital

The ear

- cranial cavity sitting above - some air cells in mastoid process; infections can occur here from ear infection, just like in sinuses. can erode through bone into cranial cavity. possible routes of infection: roots of upper teeth into maxillary sinus; nasal cavity into sphenoid or frontal sinus; venous drainage or mastoid process

muscles of larynx

- create sounds and move vocal folds when creating sound - anterior view: cricothyroid muscle - when shorten, thyroid cartilage rocks forwards. puts tension on vocal folds as take thyroid cartilage anteriorly. o posterior view: muscles attach to arytenoid are important in abducting and adducting vocal folds. arytenoid sit on top of cricoid cartilages. these muscle (posterior crico-arytenoid and transverse) shorten will spin arytenoid cartilage outwards - so opens up vocal folds - when lateral crico-arytenoid contracts: will spin arytenoid cartilage inwards - so close up vocal folds. - vocalis muscle reduces tension on vocal folds as tries to bring thyroid towards cricoid; so could be seen as antagonist to cricothyroid muscle

actions of cricothyroid, thyroarytenoid and lateral and posterior cricoarytenoid

- cricothyroid muscle (tensor of the vocal folds) - thyroarytenoid muscle (relaxor of the vocal folds) - lateral and posterior cricoarytenoid muscles (adductors and abductors of vocal folds respectively). The larynx is innervated by the superior laryngeal and recurrent (inferior) laryngeal nerves. The superior laryngeal has two branches; the internal laryngeal which supplies sensory innervation to the larynx above the vocal folds and the external laryngeal which supplies the cricothyroid muscle. All the other laryngeal muscles are supplied by the recurrent laryngeal. The R and L recurrent laryngeal nerves have different courses. The L loops under the aortic arch while the R loops under the R subclavian and then they both ascend adjacent to the trachea.

Cavernous sinuses

- either side of sphenoid bone - internal carotid artery pass through to emerge and supply anterior part of brain - also have many nerve (v2, v1, IV, III) going through lateral wall of sinus; exception is abducens (VI) which runs with ICA - relevance: any infection of cavernous sinus/ cavernous sinus thrombosis- can affect all cranial nerves - all cranial nerves pass here to back of orbit

Skull inferior view

- foramen magnum is where medulla turning into spinal cord exits the cavity - skull foramina is where cranial nerves and blood vessels can enter - condyle sits on top of first bone of neck (C1) and allows you to move head and backward

Ligaments that allow neck movement

- from underside of skull to odontoid peg = alar ligaments - from skull down to c2 vertebra to other side = cruciate ligaments - joint between c1 and skull: Atlanto-occipital joint - the "YES" joint - joint between c1 and c2 :Atlanto-axial joint - the "NO" joint

Bones of cranium

- frontal - parietal x2 - occipital - temporal x2 - sphenoid - ethmoid

Picture of anterior triangle of neck from front

- has platysma and sternocleidomastoid removed - thyrohyoid - thyroid cartilage to hyoid bone - sternothryoid - sternum to thyroid cartilage - omohyoid - shoulder to hyoid bone - sternohyoid - sternum to hyoid bone - mandible generally opened by mandible, but muscles help open

occipital lobe and posterior cranial fossa

- inferior part of occipital lobe, sits on top of posterior cranial fossa above tentorium cerebellum

Vessels in anterior triangle

- internal jugular vein (hidden by sternocleidomastoid) - internal carotid artery - accessory nerve (XI) - motor nerve that supplies sternocleidomastoid and trapezius

closed airway vs open airway

- is involved in tumours - important for ENT surgeons

Blood supply to nasal cavities

- largely from branches of internal carotid artery and external carotid artery - venous drainage: superior parts drain into cranial cavity (kind of detrimental flaw for when pathogens are trapped and are drained into cranial cavity)

Neural structures in posterior triangle

- largely sensory nerves supplying skin behind and in front of ear - spinal accessory nerve - for head position and scapula position

Lesions of innervation to vocal folds effects

- lesion in vagus nerve will cause complete paralysis - lesion of internal laryngeal --> loss of sensation above vocal folds; sensation important as any stimulation will cause reflex coughing - lesion of external laryngeal nerve --> paralysis of cricothyroid * superior laryngeal nerve branches travel with superior thyroid artery; hence when removal of thyroid gland can potentially damage nerves (STArtery is first branch of ECA) - lesion of recurrent laryngeal nerve--> paralysis of all muscles of larynx except cricothyroid and loss of sensation below the vocal folds * inferior thyroid artery travels with recurrent: also vulnerable in thyroid surgery * left recurrent laryngeal is particularly vulnerable to bronchial or oesophageal tumour/swollen mediastinal lymph nodes

Ligaments between vertebral bodies

- ligamenta flavus - supraspinous ligament: on top of spinous processes - interspinous ligament: limit how much you can move - longitudinal ligaments: anterior ligaments and posterior ligaments * stability and also limit motion *

hyoid bone in dissection

- many muscles attach here (beneath is infrahyoid aka strap muscle). thyroid gland is lower, wrapped around trachea

What is the nerve supply for the recti muscles?

*4 recti muscles: ◦Inferior, superior, medial and lateral *Origin: ◦Common tendinous ring *Insertion: ◦Sclera, 5mm behind corneal margin *Nerve supply: ◦Inferior, superior and medial (III) ◦Lateral (VI)

What is the origin of the recti muscles?

most superficial of biting muscles

- masseter (innervated by V3): responsible for elevating jaw and forced closure of mouth. - beneath masseter is temporalis muscle - also responsible for elevation and retraction of jaw (innervated by V3). - lateral and medial pterygoid muscle - responsible for depression of mandible; medial is also responsible for lateral movement of jaw which allows chewing (both innervated by V3) - parotid duct supplies saliva from parotid gland and pierces through buccinator muscle. contraction of buccinator pushes food to middle. supplied by FACIAL nerve. - inferior alveolar nerve - passes into mandible and supplies sensory information to the teeth in lower jaw; terminal branch is mental nerve, which supplies sensory information to the chin. - higher up is lingual nerve - supplies innervation to tongue. this is joined by the chorda tympani (from facial nerve), which supplies taste fibres to anterior 2/3 of tongue - maxillary artery (terminal branches of external carotid artery) - branch of this = middle meningeal artery which supplies meninges of brain

Facial bones

- maxilla x2 - zygoma x2 - nasal x2 - lacrimal x2 - vomer - inferior conchae x2 - palatine x 2 - mandible

Sinus drainage

- meatuses are where sinuses drain into nasal cavity - have connection to inner ear (auditory tube or pharyngotympanic tube) - and have nasolacrimal duct (on medial side) - when lacrimation occurs, they're drained to back of nasal cavity --> sniffling - spheno-ethmoidal recess --> drains into nasal cavity - ethmoidal air cells drain into rounded indentation between middle and inferior conchae - frontal sinuses - drains in as well - because of location of drainage points; difference in time which sinuses can drain depending whether head is upright or down

coronal section through skull base: mastoid air cells

- middle cranial fossa above mastoid air cells - infections can come from pharnygotympanic tube, erode bone superiorly to cause intracranial infection

Arterial blood supply

- middle meningeal artery passes inside cranial cavity and supplies meninges. passes through pterion and if bone breaks - can get large epidural bleed

Posterior cranial fossa

- more foramens and foramen magnum where spinal cord starts

What does contraction of the superior oblique eye muscle cause?

- moves eye/pupil away from midline and down . *n.b. - this is isolated and not acc in real life.

vocal folds

- muscular membranes in the larynx that produce sound - folds in and out to create vestibules - useful to know for intubation and anaesthesia

muscles help with movements of spine

- oblique help with side bending - erector spinae make spine straight

How do you view Blood Vessels of eye

- ophthalmoscope: can see diabetic retinopathy, papilloedema from trauma (causing high IOP)

chorda tympani joins which nerve

- part of facial nerve (CN VII), joins lingual nerve (from CN V3)

Nasal cavities

- permit airflow into airway - have bits of bones that project inwards into airway covered with respiratory epithelium; bones are called turbinate bones. - conchae = bones with the soft tissue on top. three pairs: superior, middle, inferior. - Spaces inbetween bones = meatus. superior meatus is between superior and middle conchae; middle is between middle and inferior conchae; inferior meatus is inferior to inferior conchae. - function: warm and humidify air and have immune function to help trap pathogens, and is important drainage route for sinuses.

Triangles of neck grey's picture

- posterior triangle mostly associated with nerves on way to neck and down to limbs - anterior triangle mostly associated with muscles associated with moving mandible, hyoid and larynx; or stabilising hyoid and larynx during swallowing

anterior and posterior triangles of neck

- posterior triangle: borders are sternocleidomastoid, trapezius and middle 1/3rd of clavicle - anterior triangle: borders are inferior border of mandible, anterior part of sternocleidomastoid, anterior border is from middle of mandible to sternum

recurrent laryngeal nerve supplies what?

- running behind thyroid gland up to the larynx - supplies muscles to the larynx and sensory innervation below the vocal folds - in thyroid surgery don't want to damage this nerve as has big effects on larynx function and for voice.

paranasal sinuses dissection

- sinuses surrounding nasal cavity - frontal sinus at top in frontal bone - sphenoid sinus is large sinus in sphenoid bone in front of pituitary fossa containing pituitary gland: * important clinically : to access pituitary gland surgically go through nose through sphenoidal sinus. sphenoidal sinus drains into back of nose through spheno-ethmoidal recess onto the top of the superior turbinate o can't see these in dissection - ethmoid sinus - lateral to nose - maxillary sinus in cheek - most of the sinuses drain into the space beneath the middle turbinate called the middle meatus. - in inferior meatus have nasolacrimal duct which drains tears from eye into nose

scalenus anterior

- sits behind sternocleidomastoid in posterior triangle - just behind scalenus anterior is major branch of brachial plexus supplying innervation to the arm. - also just behind scalenus artery is the subclavian artery; subclavian vein is in front of scalenus anterior - phrenic (C3-5) nerve runs along anterior surface which passes down to diaphragm Origin: Transverse processes of vertebrae C3-C6 Course: Down Insertion: Superior surface of rib 1 Innervation: C4-C6 Function: Elevates rib 1

Typical vertebrae

- thoracic = heart-shaped - lumbar = kidney- shaped

introductory video on chewing and swallowing

- tongue pushing food up to hard palate - buccinator muscle pushing food to centre of mouth - then moves to back of mouth through oropharynx to laryngopharynx to oesophagus - during swallowing: elevation of soft palate at back of mouth, closes naropharynx and stops food going into larynx; epiglottis retroflexes to stop food going into larynx - in nasopharynx have eustachian tube (continuous with middle ear cavity) - potential source of infection of middle ear - recess behind tongue is vallecula - on either side of laryngeal inlet have a cavity called piriform fossa (fish bones can get stuck and this is highly sensitive and painful)

Cranial base - anterior cranial fossa

- two depressions in frontal lobe because of eyes - when take out brain and turn it upside down, see ventral surface of brain (faces inferior - where can see all the cranial nerves) - ethmoid born has little holes - small holes of olfactory nerves - sphenoid bone

Endoscopic view of larynx

- two lines are vocal folds: hole in between is called rena glottidis - is seen where airway is open - ring inside the lines is the trachea - meaning breathing is taken place - when speaking; vocal folds need to be adducted to vibrate as air travels across the cords

relationship between the carotid canal and the foramen lacerum

The internal carotid artery passes from the carotid canal in the base of the skull, emerging and coursing superior to foramen lacerum as it exits the carotid canal.

Mandibular nerve (V3)

- two main branches: 1) inferior alveolar nerve - inferior dental nerve, passes down through foramen ovale ; passes into back of mandible, sensory nerve for lower dentition; terminal branch is mental nerve 2) lingual nerve - anterior 2/3 sensation of tongue; lingual nerve also receives branch from facial nerve from chorda tympani (comes out through petrotympanic fissure. information flow is bidirectional. parasympathetic outflow to submandibular ganglion and then postganglionic fibres going through salivary glands.

blood supply to posterior part of brain

- two vertebral arteries sitting on medulla (stalk at top of pic) comes from from basilar artery (which sits an anterior surface of pons) o basilar artery splits at its apex to form the two posterior cerebral arteries which supply occipital lobe and inferior part of temporal lobe

Nerve supply to vocal folds

- vagus nerve two branches: a) recurrent laryngeal (longer on left side: loops between aortic arch and pulmonary trunk. around ligamentum arteriosum which used to be ductus arteriosus); the rest of nerve carries down to form part of oesophageal plexus. the RHS recurs around right subclavian artery (much shorter). hence discrepancy in function of one side of innervation to other b) superior laryngeal nerve that splits into internal and external: internal does much more : sensation above vocal folds; sensation important as any stimulation will cause reflex coughing. external supplies cricothyroid

Typical vertebra

- vertebral body (weight bearing) and arch - articular facets: if facets are vertical - is difficult to move sideways; if horizontal - can do rotation. 1)Vertebral body -Major weight bearing part - have disks in between (water filled structure, cartilage and cell with nucleus in middle - allows flexibility between vertebrae), discs become smaller in night as dehydrated and less stretched out 2) Vertebral arch -Forms roof of vertebral canal -Has projections for attachment of muscles and ligaments -Has sites of articulation for adjacent vertebrae 3) Pedicles -Anchor the vertebral arch to the vertebral body

Testing eye muscle actions (clinical)

- when eyes move in one direction (single pursuit movement): one eye is abducting and one is adducting - LR and MR are left and right - when depress eye: two muscles can help - IR or SR; so to differentiate between two: adduct and then look down (SO), abduct and depress it is HR. extrinsic muscles also have rotational effect on eye (intorsion and extorsion)

relationship between shape of brain and skull

- with eye can see there is a bulge in anterior cranial fossa skull (pointed to in pic) for orbital socket, this corresponds with depression in brain in frontal lobe in orbitofrontal cortex - more posteriorly, cut end of optic nerve in skull as passes into eye; can see cut end of optic nerve in base of brain too - temporal lobe in brain fits snugly into middle cranial fossa - inferior part of occipital lobe, sits on top of posterior cranial fossa above tentorium cerebellum

Laryngeal cartilages

- without thyroid cartilage on it. - cricoid cartilage: has facets as there are joints between arytenoids that sit on here. - process from down of thyroid cartilage articulates with cricoid cartilage. thyroid can swing forwards and backwards

3rd nerve palsy

1) ptosis 2) eye goes down down (SO) and out eye (lat. rectus)3) dilated pupil

Pupillary light reflex pathway

-Light activates retinal ganglion cells -> fibers travel along optic nerve, optic chiasm, & brachium of superior colliculus to the pretectal area where they synapse -> fibers then travel bilaterally to the Edinger-Westphal Nucleus (pre-ganglionic parasympathetic fibers) ->fibers travel bilaterally from Edinger-Westphal on the oculomotor nerves to the Ciliary ganglion -> post-ganglionic fibers travel to the pupillary constrictor muscles to constrict the pupils.

Thoracic Inlet

Cranial entrance into the chest cavity

sneezing vs coughing

-coughing: soft palate is raised to block off nasal cavity; air comes out mouth - sneezing: soft palate is closed down; air directed posteriorly to soft palate and into nasal cavity o afferents for sneezing via V2 o afferents for coughing via X

Inspection of oral cavity (dorsum of tongue and palate)

The soft Palate is anchored to the posterior aspect of the hard palate There is a downward midline projection called the uvula Two pillars (AKA fauces): a) palatoglossal folds (anterior) b) palatopharyngeal folds (posterior) They depress the soft palate against the tongue. It can also seal off the nasopharynx from oropharynx

Cranial base - fossae

anterior cranial fossa (frontal lobe), middle cranial fossa (temporal lobe), posterior cranial fossa (cerebellum)

Which of the vertebral ligaments is likely to be damaged in a "whiplash" injury, when the neck is hyper-extended?

anterior longitudinal ligament - covers and connects the anterior aspect of the vertebral bodies

Identify the foramina through which the cranial nerves exit the skull

1 - cribiform plate 2 - optic canal 3 - superior orbital fissure 4 - superior orbital fissure 5i - superior orbital fissure 5ii - foramen rotundum 5iii - formamen ovale 6 - superior orbital fissure 7 - internal auditory meatus 8 - internal auditory meatus 9 - jugular foramen 10- jugular foramen 11 - jugular foramen 12 - hypoglossal canal

Constituent Parts of Larynx (JAS)

1) 3 unpaired cartilages: Cricoid Thyroid Epiglottis 2) 3 paired cartilages: Arytenoid Corniculate* (not important) Cuneiform* (really not important) 3) 2 extrinsic membranes: Thyrohyoid membrane Cricotracheal ligament 4) 2 intrinsic membranes: Cricothyroid Quadrangular* (not necessary) 5) And of course, the muscles

Suprahyoid muscle innervation

1) Anterior Innervation: Mylohyoid and Anterior belly of the Digastric Mandibular Division of the Trigeminal Nerve (V3) 2) Posterior Innervation: Stylohyoid and Posterior belly of the Digastric Facial Nerve (VII) 3) Odd one out: Geniohyoid C1 fibres via the Hypoglossal Nerve (XII)

Surface landmarks for anterior and posterior triangles of neck

1) Anterior Triangle: Supra and Infrahyoid muscles 2) Posterior Triangle: Important Nerves and vessles

Level of body of hyoid

1) C1 open mouth 2) C2 superior cervical ganglion 3) C3 body of hyoid 4) a) C4 upper border of thyroid cartilage (superior to laryngeal prominence, has suprahyoid and infrahyoid muscles) b) bifurcation of common carotid artery into internal (supplies brain) and external carotid (supplies face and thyroid gland) 5) a) C6 cricoid cartilage (sits inferior to thyroid cartilage - important for voice production and also clinically in access point for emergency airway procedures) b) middle cervical ganglion 6) C7 inferior cervical ganglion (vertebra prominens) - superior, middle and inferior cervical ganglia are part of sympathetic nervous system - and provide sympathetic innervation up to the head. from thoracolumbar spinal cord.

Level of open mouth

Levels of neck

level of bifurcation of common carotid artery

level of cricoid cartilage

level of inferior cervical ganglion

level of middle cervical ganglion

level of superior cervical ganglion

level of the upper border of the thyroid cartilage

Pharyngeal muscles

1) Circular Muscles (All innervated by CN X) a) Superior Constrictor b) Middle Constrictor c) Inferior Constrictor 2) Longitudinal Muscles a) Salpingopharyngeus* (innervated by X) b) Palatopharyngeus (innervated by X) Important, as it is involved in closure of the oropharyngeal isthmus, part of the coughing reflex c) Stylopharyngeus (innervated by IX)

What passes through the... - Optic Canal?

1) Cribriform Plate: CN I nerve fibres 2) Optic Canal: CN II Ophthalmic Artery 3) Superior Orbital Fissure: CN III, IV, V1, VI Superior Ophthalmic Vein 4) Foramen Rotundum: CN V2 5) Foramen Ovale: CN V3 6) Foramen Spinosum: Middle Meningeal Artery & Vein 7) Carotid Canal: Internal Carotid Artery 8) Foramen Lacerum: Artery and Nerve of the Pterygoid Canal 9) Internal Acoustic Meatus: CN VII, VIII Labyrinthine Artery 10) Jugular Foramen: Internal Jugular Vein CN IX, X, XI 11) Hypoglossal Canal: - CN XII 12) Foramen Magnum: Medulla Vertebral Arteries Spinal Roots of CN XI

What passes through the... Carotid Canal?

What passes through the... Cribriform Plate?

What passes through the... Cribriform Plate? - Optic Canal? Superior Orbital Fissure? Foramen Rotundum? Foramen Ovale? Foramen Spinosum? Carotid Canal? Foramen Lacerum? Internal Acoustic Meatus? Jugular Foramen? Hypoglossal Canal? Foramen Magnum?

What passes through the... Foramen Lacerum?

What passes through the... Foramen Magnum?

What passes through the... Foramen Ovale?

What passes through the... Foramen Rotundum?

What passes through the... Foramen Spinosum?

What passes through the... Hypoglossal Canal?

What passes through the... Internal Acoustic Meatus?

What passes through the... Jugular Foramen?

What passes through the... Superior Orbital Fissure?

GSA, GVA, GSE, GVE

1) GSA: General sensation to touch, pain and temperature (V1-3, VII (ear), IX and X (throat) 2) GVA: Sensory input from viscera (IX, X) 3) GSE: Motor innervation to voluntary eye and tongue muscles (III, IV, VI, XII) 4) GVE: Motor innervation to smooth muscle and glands (IIIsympathetic, VII, IX, X)

Summarise the mechanisms which protect the lungs from aspiration

1) Gag reflex Sensory: Soft palate and back of tongue (predominantly IX) Motor: Pharyngeal constrictors (X) 2) Swallowing 3) Sneezing 4) Coughing

Branches of the facial nerve (not just the extracranial component)

1) Greater petrosal nerve Carries fibres to the palate, nasopharynx and lacrimal gland 2) Nerve to the stapedius Carries fibres to the middle ear and stapedius muscle 3) Chorda tympani Carries fibres to the tongue and salivary glands 4) Posterior auricular nerve Carries fibres to occipitofrontalis auricularis 5) Extracranial component Muscles of facial expression TZBMC Posterior belly of digastric and stylohyoid

Tongue muscles

1) Hyoglossus Attached to the hyoid bone Depresses the tongue - (XII) 2) Styloglossus Attached to the styloid process Elevate and retract tongue - (XII) 3) Genioglossus Attached to the mandible and hyoid bone Protrudes the tongue - (XII) 4) Palatoglossus Aponeurosis* of palate Doesn't really do much to the tongue Helps to seal off oral cavity from oropharynx However do learn its innervation: Vagus nerve

What could cause Lymphoedema?

1) Infection (painful): Reactive Local - Generalised 2) Cancer (hard) Lymphoma Metastases **As lymph nodes drain from superficial to deep, if metastases are suspected, the deep cervical chain is also excised.

Intrinsic and extrinic muscles of the orbit

1) Intrinsic muscles are involved in changing the size of the pupil and shape of the lens (3) a) Dilator pupillae - sympathetic b) Sphincter pupillae - parasympathetic c) Ciliary muscle - parasympathetic 2) Extrinsic muscles are involved in elevating the eyelid and moving the eyeball (8) a) 4 recti b) 2 obliques c) Eyelid muscles - LPS and orbicularis oculi

Ocular Recti

1) Lateral rectus (VI) ABduction 2) Medial rectus (III) ADduction 3) Superior rectus (III) Elevation and ADduction 4) Inferior rectus (III) Depression and ADduction

Insertion and origins of all the extraocular muscles

1) Levator palpebrae superioris - origin on the lesser wing of the sphenoid and insertion into the skin of the upper eyelid and the superior tarsal plate. 2) • Superior rectus - origin in the common tendinous ring at the back of the orbit and insertion to globe of eye anterior to its equator. 3) • Inferior oblique - originates in the lower orbital nasal wall and inserts into the posterior globe of the eye • lateral rectus - origin in the common tendinous ring at the back of the orbit and insertion to globe of eye anterior to its equator 4) • Medial rectus - origin in the common tendinous ring at the back of the orbit and insertion to globe of eye anterior to its equator 5)• Inferior rectus - origin in the common tendinous ring at the back of the orbit and insertion to globe of eye anterior to its equator 6) • Superior oblique - origin at the back of the orbit, passes through trochlear and inserts into posterior globe of the eye

Muscles of mastication - superficial

1) Masseter ◦zygomatic arch to lat surface of ramus and angle of mandible ◦elevates mandible (allows forced closure of mouth) o can feel it bulging when clench teeth - good test of motor function of mandibular branch of trigeminal nerve 2) Temporalis ◦temporal fossa to coronoid process of mandible ◦elevates and retracts mandible o very thin muscle and fan shape * buccinator pushes food towards centre of mouth - is innervated from facial nerve (when suck in your cheeks that's buccinator working). all other muscles of mastication from trigeminal nerve.

Innervation to nasal cavities

1) Olfactory nerve (I) -Olfaction 2) Trigeminal nerve (V) -V1 - anterior region, V2 - posterior region 3) Facial nerve (VII) -Glands 4) Sympathetic nerves (from T1) -Vascular smooth muscle

Blood vessels of eye

1) Ophthalmic artery, which supplies: ◦central artery of the retina ◦muscular branches ◦ciliary ◦lacrimal ◦supratrochlear ◦supraorbital 2) Ophthalmic veins: ◦superior ( drains into cavernous sinus) ◦inferior (drains into pterygoid plexus)

What are the ophthalmic veins and where do they drain into?

Nerves of the Orbit

1) Optic ◦Ganglion cell axons 2) Oculomotor ◦Two rami ◦Motor fibres to MR, SR, IR, IO & LPS muscles ◦Parasympathetic fibres 3) Trochlear ◦Motor fibres to SO 4) Abducens ◦Motor fibres to LR 5) Trigeminal *Ophthalmic (V1) branches a) Lacrimal: b) Frontal: supratrochlear supraorbital c) Nasociliary: branch to ciliary ganglion ethmoidal infratrochlear 6) ciliary ganglion ◦parasympathetic ◦preganglionic fibres in inferior ramus of oculomotor ◦postganglionic fibres in short ciliary nerves ◦sphincter pupillae & ciliary muscle of eye

What are the three orbital foramina?

1) Optic canal: ◦Optic nerve (II) ◦Ophthalmic artery - main blood supply to eye 2) Inferior orbital fissure: ◦Maxillary nerve (V2) ◦Infraorbital vessels 3) Superior orbital fissure: - all cranial nerves involved in extrinsic muscle function pass here ◦Ophthalmic nerve (V1), Oculomotor (III), Trochlear (IV), Abducens (VI) ◦Ophthalmic vessels ◦Sympathetic fibres

What passes through the inferior orbital fissure?

What passes through the optic canal?

What passes through the superior orbital fissure?

Salivary Glands

1) Parotid, (serous secretion, innervated by glossopharyngeal via the otic ganglion) Parotid gland drains via parotid duct, which opens into the oral cavity lateral and superior to the second upper premolar 2) Submandibular (serous, facial nerve via the submandibular ganglion) 3) Sublingual (mucous, facial nerve via the submandibular ganglion)

Vagus nerve course in neck

**Exits cranium via which foramen? Jugular foramen **Innervates: Larynx Heart Lungs GI tract **Travels in the carotid sheath **How would you test this nerve? Gag reflex

Nasociliary and ciliary ganglion

*Ophthalmic (V1) branches a) Lacrimal: b) Frontal: supratrochlear supraorbital c) Nasociliary: branch to ciliary ganglion ethmoidal infratrochlear 6) ciliary ganglion ◦parasympathetic ◦preganglionic fibres in inferior ramus of oculomotor ◦postganglionic fibres in short ciliary nerves ◦sphincter pupillae & ciliary muscle of eye * In pic: medial rectus underneath nasociliary branch

Innervation of larynx

*Superior laryngeal nerve: a) Internal laryngeal nerve: All sensation above the vocal folds b) External laryngeal nerve: Cricothyroid muscle only *Recurrent laryngeal nerve All sensation below the vocal folds All muscles of the larynx except cricothyroid

Atypical rib C2

- dens of axis is the vertebral body of c1 that is attached to c2 - gives joint a range of motion

Sensation to the tongue

1) Anterior two thirds: Supplied by the lingual nerve General sensation - V3, lingual nerve Taste - Facial (VII), chorda tympani branch which joins lingual nerve 2) Posterior third: General sensation and taste - Glossopharyngeal (IX) 3) Epiglottic vallecula and posterior reaches of buccal cavity: Vagus (X)

What does ophthalmic artery supply?

Tympanic Cavity Netters

1) mastoid antrum 2) incus 3) chorda tympani (branch of CN VIII) 4) tensor tympani muscle and tendon (cut) 5) handle of malleus 6) auditory tube (eustachian) 7) tympanic membrane 8) styloid process 9) facial nerve (CN VII) 10) mastoid cells **Comment: The middle ear consists of the tympanic cavity and 3 ossicles, 2 of which are shown in this image (malleus and incus). The lateral wall of the tympanic cavity shows the eardrum attached to the handle of the malleus, the tensor tympani muscle, which dampens excessive vibration of the malleus, and the pharyngotympanic (auditory, eustachian) tube. This tube permits air to enter or leave the middle ear cavity and aids in the equalization of the air pressure within the middle ear. **Clinical: Very loud sounds may damage the ear. In part, the tensor tympani muscle and stapedius muscle (not shown) help to mitigate excessive vibrations of the ear ossicles.

Muscles of The Larynx

The muscles in the larynx are involved in PHONATION and PROTECTION of the airway: a) Movement of the cartilages (thyroid and arytenoid) will cause movement of the vocal ligaments, resulting in altered phonation. b) Movement of the arytenoid will cause movement of the vestibular ligament too, which has a protective function of the airway. b) Movement of the epiglottis will cover the pharyngeal isthmus and also serves a protective purpose

Inferior branch of oculomotor nerve (JAS)

Along the inferior branch, the GSE component divides into 3 to innervate: a) Medial rectus b) Inferior rectus c) Inferior oblique - The oculomotor nerve also carries the efferent parasympathetic fibres (III) These fibres travel along the inferior branch to the ciliary ganglion From here, the fibres travel along the ciliary nerves of V1 with T1 sympathetic fibres to the sphincter pupillae and ciliary body. *Sphincter pupillae - supplied by the parasympathetic fibres by way of short ciliary nerves and its contraction results in constriction of the pupil

Deep intrinsic muscles of back

"Iliocostalis, longissimus and spinalis are a group of deep intrinsic muscles, collectively known as the erector spinae. These muscles are important in stabilising and controlling the movement of the vertebral column.

External carotid artery branches

"Seven Angry Ladies Fighting Over PMS" -Superior thyroid -Ascending pharyngeal -Lingual -Facial (goes round inferior border of mandible before up to media campus of eye; has loop in it for leeway and movement of facial artery) -Occipital -Posterior auricular -Maxillary (middle meningeal originates here, pierces skull through foramen spinosum) -Superficial Temporal

Inferior oblique muscle

* Origin: Orbital surface of maxilla. *Insertion: Posterior/inferior quadrant of eyeball. *Innervation: Oculomotor. *Function: Extorsion*, Elevation and abduction

Ligaments of the vertebral column

* Supraspinous ligaments - connects the tips of the spinous processes * Interspinous ligaments - between adjacent spinous processes * Ligamenta flava - between adjacent vertebral arches * Posterior longitudinal ligament - runs within the vertebral canal on the posterior aspect of the vertebral bodies * Anterior longitudinal ligament - covers and connects the anterior aspect of the vertebral bodies

Explain likely consequences of disease or injury of recurrent laryngeal nerve and of the superior part of the cervical sympathetic chain

* The superior laryngeal nerve travels with the superior thyroid artery, which is a branch of: External carotid artery. * Hence, a lesion to this artery can affect action of the cricothyroid *The recurrent laryngeal nerve passes upward and generally behind the inferior thyroid artery *This makes it vulnerable to injury during surgery that involves ligating (tying up) the inferior thyroid artery *Additionally, a bronchial/oesophageal tumour, or mediastinal lymphadenopathy can compress the nerve resulting in hoarseness, breathlessness or both This can be remembered by the fact that the inferior thyroid artery will also supply the superior oesophagus and the trachea*

Posterior auricular nerve and extracranial nerve paths

**4th branch of facial - posterior auricular: The rest of the nerve exits the petrous bone via the stylomastoid foramen, then the 4th branch (p. auricular) is given off **5th branch - extracranial component" The remaining component of the facial nerve is referred to as the extracranial component of the facial nerve Supplies the muscles of facial expression

Medial pterygoid

**Attachments*: Lateral pterygoid plate and maxilla Angle of the mandible **Function at the TMJ Elevation and protraction Lateral movement ***To keep it simple, all the muscles elevate the mandible Except for the lateral pterygoids, and their main function is protraction The temporalis is involved in retraction The deep muscles (pterygoids) are involved in protraction***

Lateral Pterygoid

**Attachments*: Lateral pterygoid plate and sphenoid Neck of the mandible **Function at the TMJ Protraction Depression ***To keep it simple, all the muscles elevate the mandible Except for the lateral pterygoids, and their main function is protraction The temporalis is involved in retraction The deep muscles (pterygoids) are involved in protraction***

Temporalis muscle

**Attachments: Temporal fossa Coronoid process of the mandible **Function at the TMJ: Elevation and retraction ***To keep it simple, all the muscles elevate the mandible Except for the lateral pterygoids, and their main function is protraction The temporalis is involved in retraction The deep muscles (pterygoids) are involved in protraction***

Masseter muscle

**Attachments: Zygomatic arch Lateral surface of the ramus of the mandible **Function at the TMJ: Elevation ***To keep it simple, all the muscles elevate the mandible Except for the lateral pterygoids, and their main function is protraction The temporalis is involved in retraction The deep muscles (pterygoids) are involved in protraction***

Nerves involved in coughing and sneezing

**Coughing: Afferent - CN X Efferent - CN V3, CN X **Sneezing: Afferent - CN V2 (also CN 1) Efferent - CN X

Spinal accessory course in neck

**Exits cranium via which foramen? Jugular foramen **Innervates sternocleidomastoid and trapezius **Superficial location of the nerve in the posterior triangle makes it susceptible to injury **How would you test this nerve? Raised shoulders

Summary of Paranasal Sinuses (JAS)

**Extensions of nasal cavity into surrounding bones **4 of them, frontal, sphenoidal, ethmoid air cells and maxillary **Mostly drain into the middle meatus: Except for the sphenoid sinus which drains into the sphenoethmoidal recess **Innervated by: Frontal, sphenoid and ethmoid: Ophthalmic division of trigeminal (V1) Maxillary: Maxillary division of trigeminal (V2)

Branches of the External Carotids

**Inferior to Superior: 1) Superior thyroid 2) Ascending Pharyngeal 3) Lingual 4) Facial 5) Occipital 6) Posterior auricular 7) Maxillary 8) Superficial temporal remember: Some Anatomists Like F****** Over Poor Medical Students

Summary of motor and sensory functions of facial nerve

**Motor: a) Muscles of facial expression and posterior suprahyoid muscles b) Stapedius c) Parasympathetic to lacrimal gland, salivary glands, mucous membranes of nasal cavity **Sensory a) Taste anterior 2/3 tongue b) General sensation to external auditory meatus and auricle

Phrenic Nerve course in neck

**Originates from anterior rami of: C3,4,5 (keeps the diaphragm alive) **Motor to diaphragm and sensory to peritoneum and pleura around diaphragm **In posterior triangle **Relation to the scalenus anterior? Lies Anteriorly to scalenus anterior **Enters thorax between subclavian artery and vein

Origins of the four recti muscles

**Origins: The COMMON TENDINOUS RING **Insertions: Sclera: 5mm behind the corneal margin ** Innervation: Superior: Superior division of III Medial: Inferior division of III Inferior: Inferior division of III Lateral: Abducens nerve (VI)

Phases of swallowing

**PHASE 1: ORAL (V, VII, IX, X, XII) - VOLUNTARY Food is chewed by the muscles of mastication (V3, see session 2.2). Bolus is held on tongue. Elevation of soft palate, tensor and levator palatini (Mandibular V3 and Vagus X, respectively). Bolus into oropharynx, done by the tongue (XII). Airway is still OPEN. **PHASE 2: PHARYNGEAL (IX, X, XII) - REFLEX Triggered when bolus hits pharyngeal arch, tongue (XII) retracts pushing bolus into pharynx Airway CLOSED - action of pharyngeal muscles (X) Bolus propelled through pharynx (pharyngeal constrictors, X) **PHASE 3: OESOPHAGEAL (IX, X) Oesophagus opened, airway closed, breath held. Bolus propelled through oesophagus

Paths of nerve to stapedius and chorda tympani

**The 2nd branch of facial nerve - nerve to the stapedius: GSA fibres travel to the middle ear where they receive sensation Special efferent fibres travel to the stapedius **The 3rd branch - chorda tympani

Falx cerebri (JAS)

**The falx cerebri (dural fold) exists within the longitudinal cerebral fissure and thus exists between: The left hemisphere The right hemisphere **The tentorium cerebelli dural fold exists between the Occipital lobes Cerebellum and brainstem

Where does tentorium cerebellum exit?

**The tentorium cerebelli dural fold exists between the Occipital lobes Cerebellum and brainstem **The falx cerebri (dural fold) exists within the longitudinal cerebral fissure and thus exists between: The left hemisphere The right hemisphere

What fibres does chorda tympani carry?

**What does it do? SVA taste and GVE parasympathetic fibres to the tongue and salivary glands branch off as the chorda tympani **The chorda tympani will travel through the petrous bone into the middle ear as shown on the right. **Where does it exit the cranium? Petrotympanic fissure **Which V3 nerve branch does it join? lingual nerve (V3) in the infratemporal fossa

What is the insertion of the recti muscles?

Digastric Muscle (anterior belly) (JAS)

*Attachments: Internal aspect of mandible (digastric fossa*) Tendon (attached to hyoid) *Innervation? V3 * Function? Depresses the mandible Elevates and protracts the hyoid

Geniohyoid muscle (JAS)

*Attachments: Internal aspect of mandible (inferior glenoid tubercles*) Body of hyoid *Innervation? C1 fibres, via hypoglossal *Function? Protracts the hyoid Depresses the mandible

Digastric Muscle (posterior belly) (JAS)

*Attachments: Mastoid process Tendon (attached to body of hyoid) *Innervation? VII *Function? Retracts and elevates the hyoid

Sternohyoid muscle (JAS)

*Attachments: Posterior aspect of manubrium Body of hyoid *Innervation? Ansa cervicalis *Function? Depresses hyoid after swallowing

Sternothyroid muscle (JAS)

*Attachments: Posterior surface of manubrium Thyroid cartilage (oblique line*) *Innervation? Ansa cervicalis *Function? Depresses the larynx

Stylohyoid muscle (JAS)

*Attachments: Styloid process Body of hyoid bone *Innervation? VII *Function? Retracts and elevates the hyoid

Omohyoid muscle (JAS)

*Attachments: Sup. border of scapula Body of hyoid Anchored to the clavicle by fibrous tissue *Innervation? Ansa cervicalis *Function? Depresses hyoid

Thyrohyoid muscle (JAS)

*Attachments: Thyroid cartilage (oblique line*) Greater horn* of hyoid *Innervation? C1 via hypoglossal *Function? Depresses the hyoid Elevates the larynx

Why would you use the carotid pulse?

Easy to find Assess rhythm Time murmurs If radial pulse cannot be felt e.g. low blood pressure Used to locate jugular vein (USS)

Fascia of the neck

*Superficial fascia:* subcutaneous tissue - Platysma, cutaneous nerves and vessels, fat *Deep fascial layers* - *Pretracheal fascia ->* anterior neck, hyoid to thorax where it blends with fibrous pericardium over heart - *Prevertebral fascia ->* encloses vertebral column and associated muscles, roots of brachial and cervical plexus, sympathetic trunk --> *Alar fascia:* anterior subdivision of prevertebral fascia that bridges between the transverse processes - *Carotid sheath ->* extends from base of skull to root of neck --> Encloses common and internal carotid arteries, internal jugular vein, vagus nerve, and fibers of carotid plexuses

position of tentorium cerebelli on dissection

*tentorium cerebelli - partitions cranial cavity: posterior fossa from middle and anterior fossae

Cricothyroid joint

If the anterior thyroid rocks ANTERIORLY then this will cause STRETCHING of the vocal ligament *Ensure that you can visualise the movement at this joint*

Middle cranial fossa

In foramen lacerum, the internal carotid artery passes through into brain. blood supply to brain comes through carotid and vertebral systems. - foramen ovale contains nerves going through to face - temporal lobe sitting here

Which artery arises from the maxillary artery?

Middle meningeal

Platysma muscle

Muscle of the neck that moves the mandible down. Broad muscle extending from the chest and shoulder muscles to the side of the chin; responsible for lowering the lower jaw and lip. thin laye r of muscle covering anterior aspect of neck

Procedure preparation for central venous cannulation

*ultrasound guided 1.Decide cannulation site based on patient and familiarity of operator with technique 2.Obtain consent (verbal/written) 3.Position patient for IJV or SV: head down (Trendelenburg), turn head to contralateral side; (supine for FV) 4.Attach monitoring ECG, BP, Sats 5.Use aseptic technique: scrub hands, put on mask, gown and sterile gloves. 6.Check equipment, attach 3-way taps, flush line 7.Clean and drape patient's skin 8.Identify landmarks: ultrasound > surface anatomy 9.Infiltrate local anaesthetic to skin and SC tissues (10mls of 1% lignocaine) 10.Insert cannula using a Modified Seldinger Technique needle/cannula - guidewire, cut skin, dilate vessel, thread central venous catheter. 11.Watch ECG at all times (for IJV or SV) 12.Never let go of the guidewire 13.Aspirate blood from all ports, re-flush with saline, prior to suturing catheter. 14.The correct position for internal jugular lines is usually 13-15cm to the skin 15.Post insertion CXR - check for line position, absence of pneumo/haemothorax. 16.Document consent, procedure performed and CXR findings in notes. *aim to ipsilateral nipple at 45 degree angle

Protection of the airway

Nose, first line of defence - Nasal mucosa and conchae, warm and humidify inhaled air Hairs trap large particles Cilia move rubbish laden mucus to the back to be swallowed But the upper airway is a common pathway for air AND food - hence we have mechanisms to prevent aspiration

Dural folds

- Folded inner layer of dura mater (falx) - Extend into cranial cavity - Stabilize and support brain - Contain collecting veins (dural sinuses) - superior sagittal sinus is top space filled with blood, where many great veins drain into venous system. penetration of arachnoid mater into that sinus so that CSF can be reabsorbed into venous system.

What is clinical significance of cavernous sinus?

- ICA passes through cavernous sinus - many structures going into superior orbital fissure also pass through the cavernous sinus - *important clinically - as superior ophthalmic vein drains back into cavernous sinus and is potential route of infection into cranial cavity

Pterygoid canal

- Nerve of the Pterygoid Canal (vidian nerve) (Greater and Deep Petrosal Nerves) - Vessels of the Pterygoid Canal

To test orbicularis oculi (VII)?

Screw eyes shut

Blood supply to spinal cord

- One anterior and two posterior spinal arteries - Supplementary radicular arteries - Internal and external vertebral venous plexuses

Function of nerve to stapedius

Stapedius (motor) General sensation to external acoustic meatus and auricle (sensory)

Which muscle retracts and elevates the tongue to initiate swallowing?

Styloglossus. Note that the hyoglossus depresses the tongue and the genioglossus protracts the tongue

How to test vagus nerve with mouth

Test the vagus (CN X) by asking your partner to open their mouth and say aah. Observe their uvula to determine whether it rises in the midline.

CSF formation and drainage (JAS)

The choroid plexi create CSF in each ventricle. The laterals drain into the third ventricle by the interventricular foramina Then the fourth ventricle via the cerebral aqueduct Then into the subarachnoid space Via the foramina of luschka and magendie* (extra info)

Cricoarytenoid Joint

The cricoarytenoid joint allows ABduction and ADduction of the VOCAL LIGAMENTS (and also vestibular, to a smaller degree). vocal ligament is the thickened bit at top of cricothyroid ligament (top bone in pic is thyroid cartilage) The space in between the vocal ligaments is known as rima glottides*

Oculmomotor nerve two nuclei

The oculomotor nerve has 2 efferent components: a) Motor to eye muscles b) Parasympathetic motor to the sphincter pupillae and ciliary body the 2 nuclei in the brainstem from which emerge oculomotor fibres: Oculomotor (GSE - motor neurones from spinal cord to muscle*) Edinger Westphal (GVE- - autonomic functions e.g. accomodation and pupillary constriction*)

To test the ophthalmic branch of the trigeminal (V1)?

V1 is purely sensation. Therefore Test the dermatome The corneal reflex

Internal carotid artery (JAS)

Within the cranial cavity the internal carotid divides into the a) Ophthalmic branch*: This exits the cranium through (which foramen) and supplies the orbit b) Anterior cerebral artery: supplies most of the medial surface of the hemispheres and a small superior strip on the lateral surface c) Middle cerebral artery: main branch of the ICA; goes through transverse fissure of brain and supplies most of the lateral surface of the brain d) (Posterior communicating artery)

Location of venous sinuses (JAS)

a) The superior and inferior sagittal sinuses exists along the margins of the falx cerebri b) The transverse sinuses exists along the margins of the tentorium cerebelli c) The cavernous sinuses exist between the sella turcica and the temporal lobe

lingual nerve supplies what

anterior 2/3 of tongue - touch (trigeminal)

Sinuses x-ray

anterior X-ray. largely dark areas = sinuses. - frontal sinus - in frontal bone above orbits - ethmoidal air cells (honeycomb appearance) - on either side of nose - maxillary sinuses - warm air and moist: hence bacteria can grow quite well --> sinusitis

atlanto-occipital joint

articulation between the occipital condyles of the skull and the superior articular processes of the atlas (C1 vertebra). yes joint

optic canal in back of eye

contains CN II (optic nerve) and ophthalmic artery

where is route of access for emergency airway management?

cricothyroid membrane inbetween thyroid cartilage and cricoid cartilage FOR EMERGENCY. for elective: can do tracheostomy.

what are the 2 extensions of pia mater?

denticulate ligaments and filum terminale

Vallecula

depression between the epiglottis and the base of the tongue.

how to test vagus nerve

gag reflex

Bregma

junction of coronal and sagittal sutures

Cavernous sinus location

lateral to the sella turcica

What vessel is lacerated in an epidural hematoma?

middle meningeal artery

Function of greater petrosal nerve

o Greater petrosal nerve* Lacrimation (via V2 & V1) Mucous membranes of nasal cavity and palates ** Extracranial component of facial nerve Muscles of facial expression (TZBMC) Posterior belly of digastric and Stylohyoid ** Posterior auricular nerve* Occipitofrontalis Auriculares

What does external ear contain?

o The external ear consists of the auricle and external auditory meatus, which collect sound and direct it towards the tympanic membrane. The auricle is formed from a fibrocartilage skeleton, covered by firmly adherent skin. It has a lobule without a fibrocartilage skeleton inferiorly and a tragus anteriorly that overlaps the opening of the external meatus. The lateral third of the external auditory meatus is formed from fibrocartilage continuous with that of the auricle and the medial two thirds of the meatus lie within the temporal bone. The skin lining the external meatus contains ceruminous glands and the outer part is hairy. It is innervated by the auriculo-temporal nerve anteriorly and the vagus nerve posteriorly.

What does internal ear comprise of?

o The internal ear lies in the petrous temporal bone medial to the middle ear. It comprises the cochlea, vestibule and three semicircular canals.

What lies in middle ear?

o The middle ear is an irregular air space within the temporal bone. This tympanic cavity extends posteriorly into the base of the mastoid process as the tympanic antrum and anteriorly it communicates with the naso-pharynx via the pharyngotympanic (Eustachian / auditory) tube. The tympanic cavity is traversed by the chain of ossicles (maleus, incus and stapes) that transmits the vibrations of the tympanic membrane to the inner ear through the oval window in the medial wall of the middle ear.

Pupillary Light Reflex - Afferent

o The pupillary light reflex is where there is pupillary constriction in response to light o Afferent limb (dotted part of diagram) o Particular ganglion cells tuned to pick up light of a particular threshold and above. o Information is communicated along the optic nerves (II): Nasal and temporal fibres leave the eye and nasal fibres cross at the optic chiasm Firing occurs down both left and right optic tracts The relevant neurones exit and synapse with neurones in the pretectal nucleus There is then communication with the EW nucleus ** key diagram: CG = Ciliary Ganglion NIII = Oculomotor PTN - Pretectal nucleus E-W - Edinger-Westphal LBG - Lateral Geniculate Body

Borders of the anterior triangle of the neck

o anterior margin of sternocleidomastoid o inferior border of the mandible o midline of the neck

what is contained in carotid sheath?

o carotid sheath - contains common carotid artery, internal jugular vein and vagus nerve (CN X) o left common carotid arises directly from arch of aorta, but right common carotid comes from brachiocephalic

postauricular lymph node located

over the mastoid

The denticulate ligaments are lateral extensions of which structure?

pia mater. The filum terminale is the inferior extension of the pia mater, whereas the denticulate ligaments are the lateral extensions of the pia mater. The dura is the tough fibrous outer layer of the spinal meninges. The conical end of the spinal cord is known as the conus medullaris.

How to test spinal accessory nerve

raised shoulders

Where does sphenoidal sinus drain into?

sphenoethmoidal recess

What does nuchal ligament attach to?

spinous process of c7 and occipital protuberance at back of skull. continuous with supraspinous ligament. he is holding with glove.

The scalenus anterior muscle is posterior to the subclavian vein/ the subclavian artery/ the dome of the pleura/ the brachial plexus/ the trapezius muscle

subclavian vein. The scalenus anterior is found posterior to the subclavian vein, the thoracic duct, the phrenic nerve and is anterior to the subclavian artery, the dome of the pleura and the brachial plexus. A useful mnemonic for the order of structures anterior to posterior is VAN (subclavian vein, artery, and then brachial plexus) with the scalenus anterior muscle lying between the vein and artery.

Where does posterior ethmoidal sinus drain into?

superior nasal meatus

Functions of vertebral column

support, protection, movement. •Support & protection: -Body weight -Transmits forces -Supports the head -Supports the upper limbs (and aid movements) -Spinal cord •Movement: -Upper limbs and ribs (extrinsic muscles) - Postural control and movement (intrinsic muscles)

Skull - lateral view

under label for zygomatic joint is the temporo-mandibular joint that allows movement in more than one direction and often can cause issues with clicking jaws

Venous drainage of spinal cord

vertebral venous plexus azygous venous system --> SVC * internal plexus also anatomoses with basilar sinuses of brain and IVC

Management of airway

•Chin lift/ jaw thrust •Oropharyngeal or nasopharyngeal airway •Endotracheal intubation •Cricothyroidotomy •Tracheostomy

Common spinal pathology

•Low back pain •Prolapsed intervertebral disc - sciatica •Spondolysis (degeneration) •Spondylolysis (stress fracture of pars interarticularis) •Spondylolisthesis (forward displacement of vertebra) •Spondylitis (inflammation of vertebrae)

Anterior triangle of neck contains what?

•Mainly muscles: -Platysma - big sheet muscle slung underneath chin to clavicles -Mylohyoid -Digastric -Infrahyoid (strap) muscles •Carotid arteries, internal jugular vein

What bones form the floor of the orbit?

•Roof Øorbital plate of frontal bone •Floor Øorbital plate of maxilla •Lateral wall Øzygoma Øgreater wing of sphenoid •Medial wall ØFrontal process of maxilla ØLacrimal bone ØOrbital plate of ethmoid ØLesser wing of sphenoid

What bones form the lateral wall of the orbit?

What bones form the medial wall of the orbit?

What bones form the roof of the orbit?

•Roof Øorbital plate of frontal bone •Floor Øorbital plate of maxilla (thin, if something hits can blow out maxilla --> blow out fracture, and eye drops slightly and get double vision etc.) •Lateral wall Øzygoma Øgreater wing of sphenoid •Medial wall ØFrontal process of maxilla ØLacrimal bone ØOrbital plate of ethmoid (aka lamina papyracea) ØLesser wing of sphenoid

protecticle mechanisms for airway

•Swallowing •Gag reflex •Sneezing •Coughing

Posterior cricoarytenoid muscle Netters

1) Posterior cricoarytenoid muscle **Origin: Arises from the posterior surface of the laminae of the cricoid cartilage.**Insertion: Attaches to the muscular process of the arytenoid cartilage.**Action: Abducts the vocal folds and widens the rima glottidis, the space between the vocal folds.**Innervation: Recurrent (inferior) laryngeal nerve of the vagus.**Comment: The posterior cricoarytenoid muscles are extremely important because they are the only muscles that abduct the vocal folds. **Clinical: Damage to the recurrent laryngeal nerve during neck surgery (e.g., resection of the thyroid gland) can cause the vocal folds to adduct, causing hoarseness or closure of the rima glottidis, or both. This occurs because the posterior cricoarytenoid muscles are the only laryngeal muscles that abduct the vocal folds and keep the rima glottidis open. The vocal folds are controlled by the laryngeal muscles, all of which are innervated by the vagus nerve (CN X). During quiet respiration, the vocal folds are gently abducted to open the rima glottidis (space between the folds). In forced inspiration (taking a rapid, deep breath), the folds are maximally abducted by the posterior cricoarytenoid muscles, further enlarging the rima glottidis. During phonation, the folds are adducted and tensed to create a reed-like effect (similar to a reed instrument), causing vocal fold mucosal vibrations that produce sound that is then modified by the upper airway (pharynx, oral cavity, tongue, lips, nose, and paranasal sinuses). Closure of the rima glottidis occurs when holding your breath or when lifting something heavy (the Valsalva maneuver), and the folds are completely adducted.

SSA, SVA, SVE

1) SSA: Vision, hearing and balance (II, VIII) 2) SVA: Smell, taste (I, VII, IX, X) 3) SE (or SVE): Motor to muscles of facial expression, mastication and laryngeal muscles (V3, VII, IX, X)

Name six functions of the facial nerve

1) Salivation: VII provides GVE fibres from the superior salivary nucleus destined for submandibular and sublingual salivary glands via the SUBMANDIBULAR ganglion 2) Lacrimation: VII provides GVE fibres from the superior salivary nucleus destined for LACRIMAL gland via PTERYGOPALATINE ganglion. 3) Facial expression; SVE fibres to facial muscles. Tension on middle ear bones; innervation to stapedius 4) Taste; SVA fibres from anterior two thirds of tongue to the solitary nucleus via the geniculate ganglion 5) Mastication and swallowing: SVE fibres to the buccinator (mastication), raising larynx during swallowing, innervates stylohyoid and posterior belly of digastric 6) General sensation: To the external auditory meatus

What are the layers of the scalp?

1) Skin 2) Connective tissue 3) Aponeurosis 4) Loose areolar tissue 5) Periosteum

Functions of the neck

1) Structural - support and move head e.g. bones and muscles -inside prevertebral fascia (connective tissue, largely collagen, surrounds structures and maintains integrity of body parts) 2) Visceral functions - as connects mouths and airways to GIT and lungs -inside or associated with pretracheal fascia 3) Conduit for blood vessels & nerves -inside or associated with carotid sheaths

Summary of sympathetic and parasympathetic fibres to eye

1) Sympathetic fibres T1 --> superior cervical ganglion (at C2) --> Carotid plexus fibres hitchhike onto the superior branch* of the oculomotor nerve to reach the superior tarsal muscle fibres hitchhike onto the ciliary branches of the nasociliary nerve (V1) to reach the dilator pupillae and blood vessels of the eye 2) Parasympathetic fibres Edinger Westphal nucleus (III) --> Oculomotor nerve inferior branch --> ciliary ganglion --> ciliary branches of the nasociliary nerve (V1) to reach the sphincter pupillae and ciliary body. Facial nerve fibres (VII) --> eventually hitchhike onto the lacrimal nerve (V1) to reach the lacrimal gland (will be discussed again).

Deep Compartments of the Neck (JAS)

1) Vertebral: Vertebra and Musculature 2) Visceral: Trachea, Oesophagus and Thyroid 3) Vascular: Internal Jugular, Carotids and CN X (Within the carotid sheath is the vagus nerve, the common carotid artery and the internal jugular vein which is associated with the sympathetic chain behind it.)

Netters arteries of Brain: Inferior View

1) anterior communicating artery 2) anterior cerebral artery 3) internal carotid artery 4) middle cerebral artery 5) posterior communicating artery 6) posterior cerebral artery 7) superior cerebellar artery 8) basilar artery 9) anterior inferior cerebellar artery 10) vertebral artery (cut) 11) posterior inferior cerebellar artery **Comment: Branches of the internal carotid and vertebral arteries supply the brain. After entering the foramen magnum, the 2 vertebral arteries join to form the basilar artery. The latter continues forward on the anterior aspect of the brainstem, and its branches anastomose with the branches of the internal carotid artery to form the cerebral arterial circle of Willis (dashed line).The anterior circulation to the brain encompasses the anterior and middle cerebral arteries. The posterior circulation encompasses the vertebrobasilar system and the posterior cerebral artery. Generally, the arteries supplying the brain are end arteries, with insufficient anastomotic connections to compensate for occlusion of an artery. ** Clinical: The most common cause of subarachnoid hemorrhage (bleeding into the subarachnoid space) is the rupture of a saccular, or berry, aneurysm of one of the arteries of the cerebral and brainstem circulation. Berry aneurysms commonly occur at artery branch points, with about 85% occurring between the anterior cerebral, internal carotid, and middle cerebral branches.

Netters: cervical vertebrae: atlas and axis

1) articular facet of dens 2) anterior tubercle 3) anterior arch 4) transverse process 5) superior articular surface of lateral mass for occipital condyle 6) groove for vertebral artery 7) posterior arch 8) transverse foramen 9) anterior arch 10) inferior articular surface of lateral mass for axis 11) spinous process 12) superior articular facet for atlas 13) dens 14) body 15) superior articular facet for atlas 16) pedicle * Comment: The 1st cervical vertebra is the atlas. It is named after the Greek god Atlas, who is often depicted with the world on his shoulders. The atlas has no body or spine but is made of anterior and posterior arches. The transverse processes contain a foramen that transmits the vertebral vessels.The 2nd cervical vertebra is the axis. Its most characteristic feature is the dens (odontoid process). The dens articulates with the anterior arch of the atlas, providing a pivot about which the atlas and head can rotate (side-to-side action of the head, as in indicating "no"). The axis is the strongest of the cervical vertebrae. * Clinical: A blow to the top of the head may fracture the atlas, usually across the anterior and posterior arches. Such a fracture is called a Jefferson fracture. Fractures of the axis often involve the dens. A fracture may cross the neural arch between the superior and inferior articular facets. This is referred to as a "hangman" fracture.

Muscles of Larynx netters

1) aryepiglottic part of oblique arytenoid muscle 2) posterior cricoarytenoid muscle 3) thyroepiglottic part of thyroarytenoid muscle 4) thyroarytenoid muscle 5) lateral cricoarytenoid muscle 6) vocalis muscle 7) vocal ligament 8) conus elasticus **Comment: The muscles of the larynx are small. They act on the laryngeal cartilages.The most superior portion of the conus elasticus is thickened and forms the vocal ligament. The vocal folds themselves contain a small amount of muscle called the vocalis muscle, which is derived from some of the fibers of the thyroarytenoid muscle.With the exception of the cricothyroid, all the intrinsic muscles of the larynx are innervated by the recurrent laryngeal nerve of the vagus. All of these muscles are derived embryologically from the 4th through 6th pharyngeal (branchial) arches. **Clinical: The vocal folds are controlled by the laryngeal muscles, all of which are innervated by the vagus nerve (CN X). During quiet respiration, the vocal folds are gently abducted to open the rima glottidis (space between the folds). In forced inspiration (taking a rapid, deep breath), the folds are maximally abducted by the posterior cricoarytenoid muscles, further enlarging the rima glottidis. During phonation, the folds are adducted and tensed (the vocalis muscle assists with tensing the folds) to create a reed-like effect (similar to a reed musical instrument), causing vocal fold mucosal vibrations that produce sound that is then modified by the upper airway (pharynx, oral cavity, tongue, lips, nose and paranasal sinuses). Closure of the rima glottidis occurs when holding your breath or when lifting something heavy (the Valsalva maneuver), and the folds are completely adducted.

Mandibular Nerve (CN V3) Netters

1) auriculotemporal nerve 2) chorda tympani 3) lingual nerve 4) inferior alveolar nerve (cut) 5) nerve to mylohyoid muscle 6) mental nerve 7) submandibular ganglion 8) buccal nerve and buccinator muscle 9) mandibular nerve (CN V3) (anterior and posterior division) **Comment: The mandibular division of the trigeminal nerve exits the skull through the foramen ovale and divides into sensory and motor components. This nerve provides motor control to many of the muscles derived from the 1st branchial arch, most notably the muscles of mastication. The sensory components are represented largely by the auriculotemporal, buccal, lingual, and inferior alveolar nerves (the nerve to the mylohyoid muscle branches off the inferior alveolar nerve).Preganglionic parasympathetic fibers arising from the facial nerve join the lingual nerve via the chorda tympani nerve to synapse in the submandibular ganglion. These postganglionic parasympathetics then innervate the sublingual and submandibular salivary glands and the minor salivary glands of the mandibular submucosa. **Clinical: Trigeminal neuralgia (tic douloureux) is a neurologic condition characterized by episodes of brief, intense facial pain over 1 of the 3 regions of distribution of CN V. The pain is so intense that the patient often "winces," which produces a facial muscle tic. The etiology is uncertain but could be from vascular compression of the CN V sensory ganglion and usually is triggered by touch and drafts of cool air on the face.

Netters Salivary Glands

1) branches of facial nerve (CN VII) 2) transverse facial artery 3) parotid duct 4) sublingual gland 5) submandibular duct 6) submandibular gland 7) parotid gland **Comment: The parotid gland empties into the oral cavity via the parotid duct. The submandibular gland empties into the floor of the mouth via the submandibular duct, which lies beneath the oral mucosa in close relationship to the lingual nerve. The sublingual salivary gland opens through several small ducts beneath the anterior tongue.The parotid gland is a totally serous gland, whereas the submandibular salivary gland is mostly serous and partially mucous. The sublingual salivary gland is almost completely mucous.Minor salivary glands exist in the mucosa of the hard palate, cheeks, tongue, and lips. ** Clinical: Sometimes a small calculus (stone) can obstruct a parotid or submandibular salivary gland duct. Additionally, both glands may harbor a tumor, necessitating their resection. In the case of the parotid gland, great care must be taken by the surgeon to spare the terminal branches of the facial nerve, which passes through the parotid gland after its exit from the stylomastoid foramen.

Muscles of Facial Expression: Lateral View (deeper) Netters

1) buccinator muscle 2) zygomaticus minor muscle 3) zygomaticus major muscle 4) depressor anguli muscle 5) depressor labii inferioris muscle 6) mentalis muscle **Origin: Buccinator muscle arises from the mandible, pterygomandibular raphe, and alveolar processes of the maxilla and mandible. **Insertion: Buccinator muscle attaches to the angle of the mouth. **Action: Contraction of the buccinator muscle presses the cheek against the molar teeth and aids in chewing. This muscle also can expel air from the mouth, as when a musician plays a woodwind or brass instrument. **Innervation: Terminal branches of the facial nerve; buccal branch. **Comment: By pressing the cheek against the teeth, the buccinator holds food between the molars. When the muscle contracts too forcefully during chewing, the teeth bite the cheek.The term buccinator is Latin for "trumpet player." This muscle may be well developed in a musician who plays a brass instrument. The buccinator is a muscle of facial expression.Fibers of the buccinator muscle blend with other muscles around the mouth. **Clinical: All of the muscles of facial expression are derived embryologically from the 2nd pharyngeal (branchial) arch and are innervated by the terminal branches of the facial nerve (CN VII). Acute, unilateral facial palsy is the most common cause of facial muscle weakness and is called Bell's palsy. In Bell's palsy, paralysis of the buccinator muscle would result in an inability to ipsilaterally suck one's cheek inward.

Netters: internal craniocervical ligaments

1) capsule of atlantooccipital joint 2) capsule of lateral atlantoaxial joint 3) capsule of zygapophysial joint (C2-3) 4) tectorial membrane 5) posterior longitudinal ligament 6) alar ligaments 7) atlas (C1) 8) axis (C2) 9) cruciate ligament (superior longitudinal band; transverse ligament of atlas; inferior longitudinal band) * Comment: The atlantooccipital joint is a biaxial condyloid synovial joint between the atlas and the occipital condyles. It permits flexion and extension, as when the head is nodded up and down, and some lateral bending.The atlantoaxial joints are uniaxial synovial joints. They consist of plane joints associated with the articular facets and a median pivot joint between the dens of the axis and the anterior arch of the atlas. The atlantoaxial joint permits the atlas and head to be rotated as a single unit, as when the head is turned from side to side.These joints are reinforced by ligaments, especially the cruciate and alar ligaments. The alar ligaments limit rotation. *Clinical: Osteoarthritis is the most common form of arthritis and often involves erosion of the articular cartilage of weight-bearing joints, including the cervical spine. Extensive thinning of the intervertebral discs and of the cartilage covering the facet joints can lead to hyperextension of the cervical spine, narrowing of the intervertebral foramen, and the potential for impingement of the spinal nerves exiting the intervertebral foramen.

Pharynx: Opened Posterior View Netters

1) choanae 2) nasopharynx 3) oropharynx 4) laryngopharynz 5) piriform fossa 6) epiglottis 7) uvula 8) soft palate **Comment: The pharynx consists of the nasopharynx, oropharynx, and laryngopharynx. The nasopharynx lies directly behind the nasal cavities, or choanae. The oropharynx lies between the soft palate and epiglottis, directly behind the oral cavity. The laryngopharynx (also called the hypopharynx) is the lower portion of the pharynx; it lies between the epiglottis and the beginning of the esophagus.During swallowing, food moves from the oral cavity into the oropharynx, prompting the soft palate to rise and seal off the nasopharynx. The epiglottis bends downward, while the laryngeal apparatus moves upward, closing off the laryngeal inlet. The bolus of food cascades around the epiglottis and passes through the piriform fossae to enter the upper esophagus. **Clinical: Small bones (fish bones) can become lodged in the piriform fossae, causing great pain and a feeling of choking or gagging. Caution must be exercised when removing the bone so as not to damage the underlying mucosa because the internal branch of the superior laryngeal nerve (sensory to the laryngopharynx and larynx above the vocal folds) lies just beneath this mucosa.

Netters Oculomotor, Trochlear, and Abducens Nerves: Schema

1) ciliary ganglion 2) short ciliary nerves 3) inferior division of oculomotor nerve 4) pterygopalatine ganglion 5) abducens nerve (CNVI) 6) ophthalmic nerve (CN V1) 7) Oculomotor nerve (CN III) 8) Trochlear nerve (CN IV) **Comment: This schema shows the motor innervation to the extraocular muscles (from CN III, CN IV, and CN VI) and the autonomic fibers. Parasympathetic fibers arise in the brainstem and course with the oculomotor nerve to the ciliary ganglion. Postganglionic parasympathetics innervate the ciliary muscle (which accommodates the lens) and the sphincter muscle of the pupil.Sympathetic fibers that synapse in the superior cervical ganglion send postganglionic fibers to the dilator muscle of the pupil.Sensory innervation to the orbit arises from the ophthalmic division of the trigeminal nerve. **Clinical: Unilateral damage to the oculomotor nerve (CN III) can paralyze the 4 extraocular muscles innervated by this nerve (superior, medial, and inferior rectus muscles and inferior oblique muscle) and the levator palpebrae superioris muscle of the upper eyelid, causing ophthalmoplegia and ptosis (drooping of the eyelid). Additionally, parasympathetic fibers in CN III will be affected, causing pupillary dilation (unopposed sympathetic innervation of the dilator of the pupil) and an inability to accommodate the lens for close-up vision on the affected (ipsilateral) side.

Mandible: left posterior view Netters

1) condylar process 2) neck 3) pterygoid fovea 4) mandibular foramen 5) mylohyoid groove 6) submandibular fossa 7) mylohyoid line 8) sublingual fossa 9) mental spines (genial tubercles) 10) lingula 11) mandibular notch 12) coronoid process * Comment: The inferior alveolar neurovascular bundle enters the mandibular foramen and courses through the bony mandible to supply the mandibular teeth and gums.Depressions, or fossae, on the medial side of the mandible mark the locations of the submandibular and sublingual salivary glands. *Clinical: The mandible is the strongest and largest of the facial bones, and its landmarks are used for dental anesthesia via intraoral injections. Properly performed, the infiltrating anesthetic anesthetizes the inferior alveolar nerve and lingual nerve ipsilaterally (on the same side as the injection) where they lie in the pterygomandibular space proximal to the mandibular foramen. This will anesthetize the mandibular teeth (inferior alveolar nerve), the epithelium of the anterior two-thirds of the tongue (lingual nerve), all the lingual mucosa and lingual gingiva (gums) (lingual nerve), all the buccal mucosa and buccal gingiva from the premolars to the midline (mental nerve-terminal branch of the inferior alveolar nerve), and the skin of the lower lip (also via the mental nerve) ipsilaterally.

Mandible: anterolateral superior view Netters

1) condylar process (head and neck) 2) coronoid process 3) submandibular fossa 4) mylohyoid line 5) mental foramen 6) mental protuberance 7) body 8) ramus 9) mandibular notch *Comment: The mandible, or lower jaw, contains the mandibular teeth and the mandibular foramen. The inferior alveolar neurovascular bundle passes through the mandibular foramen; it innervates the mandibular teeth and supplies them with blood. The nerve ends as a cutaneous branch that exits the mental foramen (mental nerve).The condylar process of the mandible articulates with the temporal bone, forming the temporomandibular joint.Because of its vulnerable location, the mandible is the 2nd most commonly fractured facial bone (the nasal bone is the most commonly fractured). The most common sites of fracture are the cuspid (canine tooth) area and the 3rd molar area. *Clinical: Fractures of the mandible are fairly common. The mandible's U shape renders it liable to multiple fractures, which occur in over 50% of cases. The most common sites of fracture are the cuspid (canine tooth) area and the area just anterior to the 3rd molar (wisdom tooth) area. When fractured, blood oozing from the mandible may collect in the loose tissues of the floor of the mouth, above the mylohyoid muscle.

Eyeball: Horizontal Section Netters

1) cornea 2) lens 3) iris 4) ciliary body and muscle 5) optic (visual part of retina) 6) choroid 7) sclera 8) fovea centralis in macula 9) optic nerve (CN II) 10) vitreous body 11) anterior chamber **Comment: The eyeball has 3 layers: an external fibrous layer consisting of the sclera and transparent cornea; a middle vascular pigmented layer consisting of the choroid, ciliary body, and iris; and an internal neural layer, the retina.The fovea centralis, a central depression in the macula, is an avascular region that contains cones but no rods. This area provides the most acute vision.Light passes to the retina through the refractive media of the eye, which consists of the cornea, aqueous humor, lens, and vitreous humor. **Clinical: An opacity of the lens is called a cataract. Treatment often involves surgically removing the lens and implanting a plastic lens and then correcting the vision with glasses. Glaucoma is an increase in ocular pressure usually due to poor reabsorption of aqueous humor. This increased pressure may damage the retina.

Anterior and Posterior Chambers of the Eye Netters

1) cornea 2) trabecular meshwork 3) scleral venous sinus (canal of schlemm) 4) sclera 5) ciliary body 6) ciliary muscle (meridional and circular fibres) 7) zonular fibres 8) posterior chambers 9) dilator pupillae muscle 10) sphincter pupillae muscle 11) Lens 12) folds of iris 13) anterior chamber **Comment: The region of the eyeball (globe) between the zonular fibers and the iris is the posterior chamber. It communicates, by an opening in the iris (the pupil), with the anterior chamber lying between the iris and the cornea. Aqueous humor, continuously produced by the ciliary process of the ciliary body, fills these 2 chambers and is absorbed into the trabecular meshwork and scleral venous sinus.. The dilator and sphincter muscles (smooth muscles) of the iris account for the dilation and constriction of the pupillary opening. Contraction of the ciliary muscle (circular fibers) has a sphincteric action on the ciliary body such that the zonular fibers relax and the elastic lens becomes more rounded in shape, leading to accommodation for focusing on objects close to the eye. **Clinical: An increase in ocular pressure above normal limits can lead to glaucoma. This condition usually results from increased resistance to outflow of the aqueous humor via the scleral venous sinus (canal of Schlemm). This increase in intraocular pressure can damage the optic disc where axons are passing from retinal ganglion cells through the optic nerve to the brainstem.

Intrinsic Muscles of Larynx Netters

1) cricothyroid muscle 2) thyroid cartilage lamina 3) thyrohyoid membrane 4) hyoid bone 5) cricoid cartilage **Origin: Cricothyroid muscle arises from the anterolateral part of the cricoid cartilage.**Insertion: Cricothyroid muscle inserts into the inferior aspect and inferior horn of the thyroid cartilage.**Action: Cricothyroid muscle stretches and tenses the vocal folds.**Innervation: External branch of the superior laryngeal nerve of the vagus.**Comment: The cricothyroid muscle is innervated by the small, external branch of the superior laryngeal nerve of the vagus. Most of the superior laryngeal nerve continues as an internal branch that pierces the thyrohyoid membrane to provide sensory innervation above the vocal folds.This muscle, similar to the other muscles of the larynx, is derived embryologically from the 4th through 6th pharyngeal (branchial) arches. All of these laryngeal muscles are innervated by the vagus nerve. **Clinical: Damage on 1 side to the superior laryngeal nerve, a branch of the vagus nerve (CN X), will paralyze the ipsilateral cricothyroid muscle. Consequently, the voice will be affected because the ipsilateral vocal fold cannot be fully stretched and tensed. Additionally, the ipsilateral laryngeal mucosa above the level of the vocal folds will be anesthetized (the superior laryngeal nerve is sensory to the laryngeal mucosa above the vocal folds), somewhat compromising the protective gag reflex that would normally keep foreign objects from being aspirated into the larynx.

Tooth netters

1) crown 2) neck 3) root 4) enamel (substantia adamantina) 5) dentine and dentinal tubules (substantia eburnea) 6) dental pulp containing vessels and nerves 7) gingival (gum) epithelium (stratified) 8) periodontium (alveolar periosteum) 9) cement (cementum) 10) root (central) canals containing nerves and vessels 11) apical foramina * Comment: Each tooth is composed of an enamel-covered crown, dentine, and pulp. The pulp fills a central cavity and is continuous with the root canal. Blood vessels, nerves, and lymphatics enter the pulp through an apical foramen.The crown projects above the gum, or gingival surface. The narrow portion between the crown and root is called the neck. The root is embedded in the alveolar bone of the maxilla or mandible and is covered by cement, which is connected to the alveolar bone by the periodontal ligament. *Clinical: Dental caries (tooth decay) is caused by oral bacteria that convert food into acids that then form dental plaque (a combination of bacteria, food particles, and saliva). Foods rich in sugars and starch may increase one's risk for forming plaque. If not removed by brushing, the plaque can mineralize and form tartar. Acid in the dental plaque can erode the tooth enamel and create a cavity. This may occur even though enamel (an acellular mineralized tissue) is the hardest material in the human body, consisting of 96% to 98% calcium hydroxyapatite.

Suprahyoid Muscles Lateral view Netters

1) digastric muscle 2) mastoid process 3) styloid process 4) hyoglossus muscle 5) mylohyoid muscle **Origin: The digastric muscle consists of 2 bellies. The posterior belly is the longest, and it arises from the mastoid notch of the temporal bone. The anterior belly arises from the digastric fossa of the mandible. **Insertion: The 2 bellies end in an intermediate tendon that perforates the stylohyoid muscle and is connected to the body and greater horn of the hyoid bone.**Action: The digastric muscle elevates the hyoid bone and, when both muscles act together, helps the lateral pterygoid muscles open the mouth by depressing the mandible.**Innervation: The anterior belly of the digastric muscle is innervated by the mylohyoid nerve, a branch of the mandibular division of the trigeminal nerve. The posterior belly is innervated by the facial nerve.**Comment: The 2 bellies of the digastric muscle are unique because they are innervated by different cranial nerves. They are important in swallowing and mastication (chewing). **Clinical: The digastric muscles are important for opening the mouth symmetrically and are assisted by the lateral pterygoid muscles.

Schematic of Meninges netters

1) diploic veins 2) superior sagittal sinus 3) granular foveola (indentation of skull by arachnoid granulation) 4) lateral (venous) lacuna 5) inferior sagittal sinus 6) middle meningeal vessels 7) pia mater 8) subarachnoid space 9) arachnoid mater 10) dura mater (periosteal and meningeal layers) 11) cerebral vein penetrating subdural space to enter sinus 12) arachnoid granulation **Comment: The meninges include the dura mater (periosteal and meningeal layers), the arachnoid mater, and the pia mater. In the subarachnoid space, cerebral veins draining the cortex are bathed in the cerebrospinal fluid (CSF). These cerebral veins ultimately drain venous blood into the dural venous sinuses.The arachnoid granulations are tufts of arachnoid villi that project into the superior sagittal sinus and return circulating CSF to the venous system. About 500 to 700 mL of CSF is produced daily by the choroid plexus. Some CSF also is absorbed by small veins lining the brain and spinal cord. **Clinical: Veins of the scalp communicate with the dural venous sinuses via emissary veins. Because these veins are valveless, infections from the scalp can gain access to the cranial cavity. Therefore, scalp wounds should be cleansed thoroughly to prevent infection. Diploic veins (veins in the diploë, or spongy bone, of the skull) also connect to emissary veins and may drain into the dural venous sinuses.

what are the three layers of meninges?

1) dura matter = thick inelastic - 2 layers (periosteal and meningeal) 2) arachnoid mater - elastic - spider-like projections 3) pia mater - innermost, thin, delicate layer - use this to know where to insert needles, lumbar puncture and for anaesthetics e.g. for C- section, spinal anaesthetic - as layer of dura emerges from foramen magnum, the inner layer of dura continues down spinal cord, hence there's large space between dura and bone in vertebral column, but no space in the cranial cavity, unless its filled with blood

Netters: cartilages of larynx

1) epiglottis 2) hyoid bone 3) thyrohyoid membrane 4) arytenoid cartilage 5) thyroid cartilage famina 6) vocal ligament 7) median cricothyroid ligament 8) cricoid cartilage 9) trachea * Comment: The cartilages of the larynx include the thyroid cartilage, cricoid cartilage, epiglottis, and paired arytenoid, corniculate, and cuneiform cartilages.Not shown in the illustration are the cuneiform cartilages. These paired elastic cartilages lie in the aryepiglottic folds and have no articulations with other cartilages or bones.The thyroid cartilage possesses the anteriorly placed laryngeal prominence, or Adam's apple.The thyrohyoid membrane has an opening through which the internal branch of the superior laryngeal nerve (branch of the vagus nerve) enters the larynx to provide sensory innervation above the vocal folds. *Clinical: Trauma to the cartilages of the larynx may result in fractures. Consequently, the underlying laryngeal mucosa and submucosa may hemorrhage, resulting in significant edema and the potential for airway obstruction. Ultimately, such an injury may result in hoarseness as the vocal folds swell and/or are compromised by the damage (muscle or nerve damage), making speaking difficult or impossible.

Superficial Veins and Arteries of Neck Netters

1) facial artery and vein 2) retromandibular vein 3) external jugular vein 4) anterior jugular vein 5) thyroid cartilage 6) sternocleidomastoid muscle 7) trapezius muscle 8) thyroid gland 9) common carotid artery 10) internal jugular vein 11) superior thyroid artery and vein 12) external carotid artery **Comment: Superficial veins of the neck include the external jugular vein and its principal tributaries. The external jugular vein often communicates with the internal jugular vein, which lies deep within the carotid sheath.The principal arteries of the neck include major branches arising from the subclavian artery (thyrocervical and costocervical trunks) and several branches arising from the external carotid artery. **Clinical: Physicians use the internal jugular vein (or external jugular) on the right side to assess the jugular venous pulse, which provides an indication of the venous pressure in the right atrium of the heart. If the waveform pattern of the pulse is abnormal, it may indicate some pathology associated with right-sided congestive heart failure, a tricuspid valve problem, or some other abnormality. If a physician needs to gain access to the right chambers of the heart (to measure pressures), a right cardiac catheterization may be performed. The right internal jugular vein or right subclavian vein may be used and the catheter is threaded through the right brachiocephalic vein, into the superior vena cava and then into the right atrium.

Foramina of cranial base: superior view Netters

1) foramina of cribriform plate (olfactory nerve bundles) 2) optic canal (optic nerve (CNII; ophthalmic artery) 3) superior orbital fissure (oculomotor nerve (CNIII); trochlear nerve (CNIV); lacrimal, frontal and nasocilary branches of ophthalmic nerve (CNVi); abducens nerve (CNVI); superior ophthalmic vein) 4) foramen rotundum (maxillary nerve (CNVii) 5) foramen ovale (mandibular nerve (CNV3; accessory meningeal artery; lesser petrosal nerve (occasionally)) 6) foramen spinosum (middle meningeal artery and vein; meningeal branch of mandibular nerve) 7) foramen lacerum (greater petrosal nerve crosses this space) 8) carotid canal (internal carotid artery; internal carotid nerve plexus) 9) internal acoustic meatus (facial nerve (CNVII); vestibulocochlear nerve (CNVIII); labyrinthine artery) 10) jugular foramen (inferior petrosal venous sinus; glossopharyngeal nerve (CNIX); vagus nerve (CNX); accessory nerve (CNXI); sigmoid venus sinus; posterior meningeal artery) 11) hypoglossal canal (hypoglossal nerve (CNXII) 12) foramen magnum (medulla oblongata; meninges; vertebral arteries; meningeal branches of vertebral arteries; spinal roots of accessory nerves)

Muscles of Facial Expression: Lateral View Netters

1) frontal belly of occipitofrontalis muscle 2) mentalis muscle 3) depressor labii inferioris muscle 4) depressor anguli oris muscle *Origin: The frontal belly of the occipitofrontalis muscle has no bony origin. Its fibers arise from the superficial fascia and are continuous with 2 other anterior facial muscles, the procerus and the corrugator supercilii. *Insertion: The fibers of the frontal belly are directed upward. They join the epicranial aponeurosis (galea aponeurotica) anterior to the coronal suture. *Action: The frontal belly of the occipitofrontalis muscle elevates the eyebrows and wrinkles the forehead, as when a person looks surprised. *Innervation: Terminal branches of the facial nerve; temporal branch. **Comment: This epicranius muscle consists largely of the frontal and occipital bellies and an intervening epicranial aponeurosis (galea aponeurotica).As a muscle of facial expression, this cutaneous muscle lies within the layers of the superficial fascia. These muscles vary from person to person, and they often blend together. **Clinical: All of the muscles of facial expression are derived embryologically from the 2nd pharyngeal (branchial) arch and are innervated by the terminal branches of the facial nerve (CN VII). Acute, unilateral facial palsy is the most common cause of facial muscle weakness and is called Bell's palsy. In Bell's palsy, paralysis of the frontalis portion of the epicranius muscle would result in an inability to fully raise one's eyebrows and wrinkle the forehead skin.

Label skull bones: front view Netters

1) frontal bone 2) supraorbital notch (foramen) 3) nasal bone 4) lacrimal bone 5) zygomatic bone 6) infraorbital foramen 7) maxillary bone 8) mental foramen 9) mandible 10) ethmoid bone (orbital plate) 11) sphenoid bone 12) temporal bone 13) parietal bone The bones of the neurocranium are fused together at immovable, fibrous joints, such as the sutures. The 2 general classes of skull bones are the bones of the NEUROCRANIUM (8 bones), which enclose the brain, and the facial bones (14 bones) (VISCEROCRANIUM). The 8 bones of the neurocranium are the frontal, occipital, ethmoid, and sphenoid bones, a pair of temporal bones, and a pair of parietal bones. The general term cranium refers to the skeleton of the head.Associated bones of the skull include the auditory ossicles (3 in each middle ear cavity) and the unpaired hyoid bone. The skull and associated bones constitute 29 different bones (the 32 adult teeth are part of the mandible and maxilla and are not counted separately). Clinical: Midface fractures are classified clinically as Le Fort fractures:Le Fort I: horizontal fracture detaching the maxilla along the nasal floorLe Fort II: pyramidal fracture that includes both maxillae, nasal bones, infraorbital rims, and orbital floorsLe Fort III: includes the Le Fort II fracture and both zygomatic bones; may cause airway obstruction, nasolacrimal obstruction, and cerebrospinal fluid (CSF) leakage

Lateral wall of nasal cavity Netters

1) frontal bone (sinus) 2) nasal bone 3) Major alar cartilage 4) Maxillary bone (frontal process; incisive canal; palatine process; alveolar process) 5) inferior nasal concha 6) palatine bone (perpendicular plate; horizontal plate) 7) sphenoid bone (sphenoidal sinus; medial and lateral plates of pterygoid process; pterygoid hamulus of the medial plate) 8) Ethmoid bone (middle nasal concha; cribriform plate; superior nasal concha) 9) lacrimal bone *Comment: The lateral wall of the nasal cavity prominently displays the superior and middle conchae (called turbinates when covered with mucosa) of the ethmoid bone and the inferior concha. Portions of other bones, including the nasal bone, maxillary bone, lacrimal bone, palatine bone, and sphenoid bone, contribute to the lateral wall of the nasal cavity.The palatine processes of the maxillae and the horizontal plates of the palatine bones make up the hard palate. *Clinical: The pituitary gland lies in the hypophyseal fossa, a depression seen just superior to the sphenoidal sinus in the sphenoid bone. A tumor of the pituitary gland can be approached surgically through the nasal cavity by passing through the sphenoidal sinus and directly entering the hypophyseal fossa.

Netters Lateral Wall of Nasal Cavity

1) frontal sinus 2) middle nasal concha (turbinate) 3) middle nasal meatus 4) inferior nasal concha (turbinate) 5) opening of auditory tube (eustachian) 6) pharyngeal tonsil (adenoid if enlarged) 7) sphenoidal sinus 8) hypophysis (pituitary gland) in sella turcica **Comment: The lateral nasal wall is characterized by 3 nasal turbinates (called concha if not covered by mucosa). The space beneath each turbinate is the meatus.The nasolacrimal duct opens into the inferior nasal meatus. The frontal sinus and maxillary sinus open into the middle nasal meatus. Additionally, the anterior and middle ethmoidal sinuses open on the ethmoidal bulla, beneath the middle nasal turbinate. The posterior ethmoidal sinus opens in the superior meatus, and the sphenoidal sinus opens in the sphenoethmoidal recess.The vascular supply of this region is via branches of the sphenopalatine artery (from the maxillary artery), and the innervation is from the maxillary nerve or CN V2 (general sensation), CN I (olfaction), and CN VII (secretomotor fibers to the mucous glands via the pterygopalatine ganglion). **Clinical: Rhinosinusitis is an inflammation of the paranasal sinuses, especially the ethmoid and maxillary sinuses, and nasal cavity. This infection usually results from a respiratory virus or secondary bacterial infection. Nasal congestion, facial pain and pressure, discharge, fever, headache, painful maxillary teeth, and halitosis are some of the signs and symptoms.

Netters vestibulocochlear Nerve: Schema

1) geniculate ganglion (CN VII) 2) greater petrosal nerve 3) cochlear (spiral) ganglion 4) vestibulocochlear nerve (CN VIII) 5) chorda tympani nerve 6) facial canal and nerve 7) vestibular ganglion **Comment: The facial and vestibulocochlear nerves traverse the internal acoustic meatus together. The facial nerve makes a sharp bend at the level of the geniculate (sensory) ganglion of the facial nerve before descending and exiting the skull through the stylomastoid foramen. It sends preganglionic parasympathetic fibers to the pterygopalatine ganglion (via the greater petrosal nerve) and to the submandibular ganglion (via the chorda tympani nerve).The vestibulocochlear nerve carries special sensory fibers from the cochlea via the cochlear nerve (auditory) and from the vestibular apparatus via the vestibular nerve (balance). These 2 branches join and leave the inner ear via the internal acoustic meatus to pass to the brain. **Clinical: Vertigo is a symptom involving the peripheral vestibular system or its central nervous system connections and is characterized by the illusion or perception of motion. Hearing loss can be sensorineural, suggesting a disorder of the inner ear or cochlear division of CN VIII. Conductive hearing loss suggests a disorder of the external or middle ear (tympanic membrane and/or middle ear ossicles).

Netters glossopharyngeal Nerve

1) geniculate ganglion of facial nerve 2) greater petrosal nerve 3) deep petrosal nerve 4) lesser petrosal nerve 5) otic ganglion 6) auriculotemporal nerve (CN V3) 7) parotid gland 8) stylopharyngeus muscle and nerve branch from CN IX 9) pharyngeal plexus 10) carotid branch of CN IX 11) superior cervical ganglion 12) vagus nerve (CN X) 13) jugular foramen 14) glossopharyngeal nerve (CN IX) 15) inferior salivatory nucleus **Comment: The glossopharyngeal nerve innervates only 1 muscle (stylopharyngeus) but receives significant general sensory distribution from the pharynx, posterior third of the tongue, middle ear, and auditory tube. CN IX is the nerve of the 3rd pharyngeal (branchial) embryonic arch. It exits the skull via the jugular foramen.The special sense of taste (posterior third of the tongue) also is conveyed by this nerve. Cardiovascular sensory fibers include those associated with the carotid body (chemoreceptor) and carotid sinus (baroreceptor) region adjacent to the common carotid artery bifurcation. **Clinical: Placing a tongue depressor on the posterior third of the tongue elicits a gag reflex, mediated by the sensory fibers of CN IX on the posterior third of the tongue, which then triggers a gag and elevation of the soft palate, mediated largely by the vagus nerve (CN X).

Tongue Netters

1) genioglossus muscle 2) geniohyoid muscle 3) middle pharyngeal constrictor muscle 4) stylopharyngeus muscle 5) stylohyoid muscle 6) styloglossus muscle 7) palatopharyngeus muscle 8) palatoglossus muscle **Origin: Genioglossus muscle arises from the superior part of the mental spine of the mandible. **Insertion: Genioglossus muscle attaches to the dorsum of the tongue and body of the hyoid bone (inferior fibers of the muscle). **Action: The central fibers of the genioglossus, acting bilaterally, depress the tongue. Acting unilaterally, these central fibers pull the tongue to the opposite side. Its posterior fibers protrude the tongue, as in sticking the tongue out of the mouth. **Innervation: Hypoglossal nerve (CN XII). **Comment: The genioglossus is 1 of the 3 extrinsic muscles of the tongue. These extrinsic muscles move the tongue, whereas the intrinsic muscles change the tongue's shape.All of the muscles with "glossus" in their names are innervated by the hypoglossal nerve except the palatoglossus muscle, which is a muscle of both the tongue and soft palate and is innervated by the vagus nerve. **Clinical: One can easily test the hypoglossal nerve (CN XII) by asking the patient to "stick your tongue out." If ipsilateral damage to the hypoglossal nerve has occurred, the patient's tongue will deviate to the side of the lesion, with the tip of the tongue pointing ipsilaterally. This occurs because of the strong force of pull by the posterior fibers of the contralateral genioglossus, which is unopposed by the paralyzed ipsilateral fibers. This causes the tongue to protrude and then deviate beyond the midline to the unopposed side (side of the nerve lesion). Anesthesiologists pull the mandible forward, thus pulling the genioglossus and tongue forward, to clear the airway and prevent the tongue from shifting posteriorly into the oral pharynx.

Floor of Mouth: Netters

1) geniohyoid muscle 2) submandibular gland 3) submandibular duct 4) inferior alveolar nerve and artery 5) lingual nerve 6) sublingual gland 7) mylohyoid muscle **Origin: Geniohyoid muscle arises from the inferior mental spine (genial tubercle) of the mandible.**Insertion: Geniohyoid muscle attaches to the body of the hyoid bone.**Action: Geniohyoid muscle slightly elevates and draws the hyoid bone forward, shortening the floor of the mouth. This action permits the geniohyoid to act as an antagonist to the stylohyoid muscle. When the hyoid bone remains fixed, the geniohyoid muscle also helps retract and depress the mandible.**Innervation: C1 via the hypoglossal nerve (CN XII).**Comment: The digastric, stylohyoid, mylohyoid, and geniohyoid muscles are considered "suprahyoid" muscles because they lie above the hyoid bone. **Clinical: The mylohyoid and geniohyoid muscles form the floor of the mouth. Soft tissue injury in this area or fractures of the anterior mandible may result in significant bleeding in this area. These muscles are also important in multiple actions associated with the mouth.

Tongue: Netters

1) hyoglossus muscle 2) superior pharyngeal constrictor muscle 3) hyoid bone ** Origin: Hyoglossus muscle arises from the body and greater horn of the hyoid bone. **Insertion: Hyoglossus muscle attaches to the lateral and dorsal surface of the tongue. **Action: Hyoglossus muscle depresses, or pulls, the tongue into the floor of the mouth. It also retracts the tongue. **Innervation: Hypoglossal nerve (CN XII). **Comment: The hyoglossus is one of the tongue's extrinsic muscles, which alter the position of the tongue within the mouth. The intrinsic muscles of the tongue change the tongue's shape.All of the muscles with "glossus" in their names are innervated by the hypoglossal nerve except the palatoglossus muscle, which is a muscle of both the tongue and soft palate and is innervated by the vagus nerve. ** Clinical: The lingual artery, a branch of the external carotid artery in the neck, is the major blood supply to this area and can be located as it passes deep to the hyoglossus muscle. Bleeding due to soft tissue damage in this region will cause swelling as the blood accumulates in the floor of the mouth.

Cervical Plexus In Situ Netters

1) hypoglossal nerve (CNXII) 2) common cartotid artery 3) ansa cervicalis (superior root; inferior root) 4) vagus nerve (CN X) 5) subclavian artery and vein 6) phrenic nerve 7) accessory nerve (CN XI) 8) internal jugular vein 9) lesser occipital nerve 10) greater auricular nerve **Comment: The cervical plexus arises from anterior rami of C1-C4. It provides motor innervation for many of the muscles of the anterior and lateral compartments of the neck. This plexus also provides cutaneous innervation to the skin of the neck.Most of the motor contributions to the infrahyoid muscles arise from a nerve loop called the ansa cervicalis (C1-C3).The cervical plexus also gives rise to the first 2 of 3 roots contributing to the phrenic nerve (C3, C4, and C5). The phrenic nerve innervates the respiratory diaphragm. **Clinical: Unilateral trauma to the posterior cervical triangle of the neck may injure the accessory nerve (CN XI) (ipsilateral innervation of the sternocleidomastoid and trapezius muscles), the phrenic nerve (C3-C5) (innervates the ipsilateral hemi-diaphragm), or the trunks or cords of the brachial plexus. As you will see in the Upper Limb section of these flash cards, the brachial plexus is the innervation for the muscles of the shoulder, arm, forearm, and hand. The integrity of each of these nerves should be assessed when trauma is evident.

Teeth netters

1) incisive fossa 2) palatine process of maxillary bone 3) horizontal plate of palatine bone 4) greater and lesser palatine foramina 5) central incisor (one on each side; same names for teeth of the maxilla) 6) lateral incisor 7) canine 8) 1st premolar 9) 2nd premolar 10) 1st molar 11) 2nd molar 12) 3rd molar * Comment: Humans have 2 sets of teeth: the deciduous teeth, which total 20, and the permanent teeth (shown in this illustration), which total 32 (16 maxillary and 16 mandibular teeth).Permanent teeth in each quadrant of the jaw (mandible and maxilla) include 2 incisors, 1 canine, 2 premolars, and 3 molars. The 3rd molars are often referred to as the wisdom teeth.The maxillary teeth are innervated by the posterior, middle, and anterior superior alveolar branches of the maxillary nerve (CN V2). The mandibular teeth are innervated by the inferior alveolar branch of the mandibular nerve (CN V3). * Clinical: Because of its vulnerable location, the mandible is the 2nd most commonly fractured facial bone (the nasal bone is the most commonly fractured). The most common sites of fracture are the cuspid (canine tooth) area and the area just anterior to the 3rd molar.

Ear: Frontal Section Netters

1) incus 2) malleus (head) 3) tympanic membrane 4) cochlear (round) window 5) auditory tube (eustachian) 6) cochlea 7) vestibulocochlear nerve (CN VIII) 8) semicircular ducts, ampullae, utricle and saccule 9) stopes in vestibular (oval) window **Comment: The external ear consists of the auricle and the external acoustic meatus.The middle ear consists of the tympanic cavity and its 3 ossicles. The lateral wall of the tympanic cavity is formed by the tympanic membrane (eardrum). The medial wall contains the oval and round windows. The auditory ossicles include the malleus (hammer), incus (anvil), and stapes (stirrup). The middle ear connects to the nasopharynx by the auditory (eustachian) tube. Via the auditory tube, air may enter or leave the middle ear cavity and equalize middle ear pressure with atmospheric pressure.The inner ear consists of the cochlea and the vestibular apparatus. The acoustic apparatus and vestibular apparatus are innervated by CN VIII, the vestibulocochlear nerve.The external ear is innervated by sensory branches from CN V3, CN VII, and CN X. The middle ear is innervated by the glossopharyngeal nerve (CN IX). **Clinical: Acute otitis externa, better known as swimmer's ear, is an inflammation or infection of the external ear. Acute otitis media (earache) is an inflammation of the middle ear and is common in children younger than age 15.

Muscles of Pharynx: netters

1) inferior pharyngeal constrictor muscle 2) cricopharyngeal muscle (part of inferior pharyngeal constrictor muscle) 3) esophagus 4) posterior cricoarytenoid muscle 5) thyroid cartilage 6) internal branch of superior laryngeal nerve 7) epiglottis 8) root of tongue 9) choana **Origin: Inferior pharyngeal constrictor muscle arises from the oblique line of the thyroid cartilage and side of the cricoid cartilage. **Insertion: The 2 inferior pharyngeal constrictor muscles wrap posteriorly to meet and attach to the median raphe of the pharynx. **Action: Inferior pharyngeal constrictor muscle constricts the wall of the lower pharynx during swallowing. **Innervation: Pharyngeal plexus of the vagus nerve (CN X). Some minor contributions may come from the external branch of the superior laryngeal nerve and recurrent laryngeal nerves of the vagus. **Comment: The inferior pharyngeal constrictor lies largely behind the thyroid and cricoid cartilages. Its lower end is referred to as the cricopharyngeal muscle, which is continuous with the esophageal muscle fibers. The cricopharyngeal portion of this muscle is considered the superior esophageal sphincter. It contains a significant amount of elastic tissue and slow-twitch and fast-twitch muscle fibers. This allows the muscle to maintain its tone, so that it can quickly contract and relax during swallowing, belching, or vomiting. The point at which the inferior constrictor attaches to the cricoid cartilage represents the narrowest portion of the pharynx. **Clinical: Although the motor innervation of the pharyngeal constrictors is via the vagus nerve (CN X, pharyngeal plexus), the sensory innervation of all but the most superior part of the pharynx (the constrictor muscles and the mucosa lining the interior of the pharynx) is via the glossopharyngeal nerve (CN IX). Together, the fibers of CN IX and X form the pharyngeal plexus and function in concert with one another during swallowing. Injury to the pharyngeal fibers from CN X can result in difficulty swallowing (dysphagia).

Dural Venous Sinuses netters

1) inferior sagittal sinus 2) anterior and posterior intercavernous sinuses 3) sigmoid sinus 4) transverse sinus 5) occipital sinus 6) confluence of sinuses 7) superior sagittal sinus 8) straight sinus 9) great cerebral vein (of galen) **Comment: The dural venous sinuses form between the periosteal (endosteal) and meningeal layers of the dura mater. The superficial and deep regions of the brain are drained by the superior sagittal and inferior sagittal venous sinuses. Most of the venous blood from the brain collects in these dural venous sinuses and ultimately drains into the internal jugular veins and to a lesser extent into the vertebral veins.Infections can gain access to these dural venous sinuses and spread to other regions of the head. **Clinical: Much of the blood returning from the cerebral cortical areas passes from the cortical surface across the subarachnoid space, pierces the arachnoid and meningeal dural layer, and empties into the superior sagittal dural venous sinus. With aging, the brain volume decreases, and sudden motion of this smaller brain in the cranial vault, typically from falls and a bump on the head in elderly individuals, can cause a tearing of the bridging veins. When this happens, bleeding can occur between the arachnoid and meningeal dural layer, causing a subdural hematoma.

Temporomandibular joint netters

1) joint capsule 2) lateral (temporomandibular) ligament 3) sphenomandibular ligament (phantom) 4) stylomandibular ligament 5) mandibular fossa 6) articular disc 7) articular tubercle 8) joint capsule * Comment: The temporomandibular joint is the synovial joint between the mandibular fossa and the articular tubercle of the temporal bone and head of the mandible. The joint's 2 synovial cavities are separated by an articular disc of fibrocartilage.This unique joint combines an upper uniaxial gliding joint, for forward gliding (protrusion) and backward gliding (retraction) movements and some side-to-side motion. The lower joint, below the articular disc, is a uniaxial hinge joint for closing (elevation of) and opening (depression of) the jaw.This joint contains an articular capsule and is reinforced by the lateral and sphenomandibular ligaments. *Clinical: The temporomandibular joint (TMJ) has both a hinge action and a gliding or sliding action. TMJ problems affect about 25% of the population and can result from trauma, arthritis, infection, clenching or grinding of the teeth (bruxism), or displacement of the articular disc. TMJ problems are more common in women than men.

Muscles Involved in Mastication lateral view Netters

1) lateral pterygoid muscle 2) articular disc of temporomandibular joint 3) sphenomandibular ligament 4) medial pterygoid muscle 5) buccinator muscle **Origin: Lateral pterygoid muscle, a short, thick muscle, has 2 heads. The superior head arises from the infratemporal surface and infratemporal crest of the greater wing of the sphenoid bone. The inferior head arises from the lateral surface of the lateral pterygoid plate.**Insertion: The fibers of the lateral pterygoid muscle converge to insert into the pterygoid fovea on the front of the neck of the mandible, articular disc, and capsule of the temporomandibular joint.**Action: Lateral pterygoid muscle assists in opening the mouth by drawing the condyle of the mandible and articular disc of the temporomandibular joint forward. With the medial pterygoid of the same side, the lateral pterygoid protrudes the mandible. The jaw is rotated to the opposite side, producing a grinding movement.**Innervation: Mandibular division of the trigeminal nerve.**Comment: The other 3 muscles of mastication help close the jaw, whereas the lateral pterygoid opens the jaw. At the beginning of this action, it is assisted by the mylohyoid, digastric, and geniohyoid muscles.The muscles of mastication are derived embryologically from the 1st pharyngeal (branchial) arch and are innervated by the mandibular division of the trigeminal nerve (CN V3). **Clinical: Sometimes individuals clench their teeth and grind their molars while in deep sleep. This grinding action of the pterygoid muscles can erode the teeth, and people suffering from this malady should seek the attention of their health care specialist.

Levator palpebrae superioris muscle Netters

1) levator palpebrae superioris muscle **Origin: Arises from the lesser wing of the sphenoid bone, anterior and superior to the optic canal.Insertion: Attaches to the skin and tarsal plate of the upper eyelid.**Action: Raises the upper eyelid.**Innervation: Oculomotor nerve (CN III). At the distal end of this muscle, near its attachment to the tarsal plate, is a small amount of smooth muscle called the superior tarsal muscle. The fibers of the superior tarsal muscle are supplied by postganglionic sympathetic fibers of the autonomic nervous system.**Comment: Because of the dual nature of the levator palpebrae superioris muscle (it is skeletal and has a small smooth muscle component), drooping of the upper eyelid can result from a nerve lesion affecting the oculomotor nerve or the sympathetic fibers. This drooping is called ptosis. **Clinical: Ptosis can result from nerve damage at 2 different sites. Damage to the oculomotor nerve (CN III) can result in paralysis of the levator palpebrae superioris muscle and significant ptosis. Damage anywhere along the sympathetic pathway from the upper thoracic sympathetic outflow to the head, the cervical sympathetic trunk, or the superior cervical ganglion and beyond can result in denervation of the small tarsal muscle (smooth muscle) that is found at the free distal margin of the levator palpebrae superioris muscle. This will result in a mild ptosis: the ipsilateral upper eyelid droops, but only slightly.

Roof of Mouth Netters

1) levator veli palatini muscle 2) choanae 3) uvular muscle 4) palatopharyngeus muscle 5) pterygoid hamulus **Origin: Levator veli palatini muscle arises from the cartilage of the auditory tube and the petrous portion of the temporal bone.**Insertion: Levator veli palatini muscle attaches to the palatine aponeurosis of the soft palate.**Action: Levator veli palatini muscle elevates the soft palate during swallowing and yawning.**Innervation: Vagus nerve (CN X) via its pharyngeal plexus. **Comment: After the soft palate has been tensed by the tensor veli muscle (which hooks around the pterygoid hamulus), the levator elevates the palate. Note the arrangement of these muscles in the figure (posterior view). On the left side of the image the levator veli palatini muscle has been cut near its origin to allow better visualization of the tensor veli palatini muscle. ** Clinical: The levator elevates the soft palate and can be tested clinically by asking a patient to say "ah." By watching the soft palate elevate as this is done, one can look for even, symmetric elevation, indicating that the vagus nerve (CN X) is functioning properly on both sides. If there is damage to the vagus nerve on one side, the soft palate will deviate contralaterally, that is, to the normally functioning side and away from the abnormally functioning side.

Netters: prevertebral Muscles

1) longus capitis muscle 2) longus colli muscle **Origin: The longus capitis arises from the anterior tubercles of the C3-C6 vertebral transverse processes. The longus colli arises from the bodies of the T1-T3 vertebrae, the bodies of the C4-C7 vertebrae, and transverse processes of the C3-C6 vertebrae. **Insertion: The longus capitis attaches to the basilar portion of the occipital bone. The colli portion attaches to the anterior tubercle of the atlas (C1), the bodies of the C2-C4 vertebrae, and transverse processes of the C5-C6 vertebrae.**Action: Both muscles flex the neck, although the longus colli is weak. The longus colli also slightly rotates and laterally bends the neck. **Innervation: The longus capitis is supplied by the C1-C3 anterior rami. The longus colli is supplied by the C2-C6 anterior rami.**Comment: The longus capitis and longus colli lie in front of the cervical vertebrae and are often called prevertebral muscles. They help other muscles flex the cervical spine. **Clinical: These muscles and the scalenus muscles comprise anterior muscle groups often lumped together as "prevertebral" muscles. They are encased in a strong fascial sleeve called the prevertebral fascia and do not tolerate swelling well because of this tight enclosure. Just anterior to the prevertebral fascia, where it covers the bodies of the cervical vertebrae, lies the retropharyngeal space (this space is posterior to the buccopharyngeal fascia [the posterior portion of the pretracheal fascia] covering the posterior pharynx and esophagus). Infections in this vertical space may pass superiorly to the base of the skull or inferiorly into the posterior mediastinum of the thorax.

Facial Nerve Branches Netters

1) main trunk of facial nerve emerging from stylomastoid foramen 2) parotid gland 3) parotid duct 4) cervical brunch 5) marginal mandibular branch 6) facial artery and vein 7) buccal branches 8) zygomatic branches 9) temporal branches **Comment: The main trunk of the facial nerve exits through the stylomastoid foramen and, after giving off several small branches, courses through the substance of the parotid gland. It ends as a plexus of 5 major terminal branches that innervate the muscles of facial expression.The 5 groups of terminal branches are the temporal, zygomatic, buccal, marginal mandibular, and cervical branches. A mnemonic—To Zanzibar By Motor Car (named from superior to inferior)—might help in remembering the names of these 5 terminal branches. **Clinical: An infection, usually caused by the herpes simplex virus, of the facial nerve (CN VII) can cause acute unilateral paralysis of the muscles of facial expression, a condition called Bell's palsy. Facial expression on the affected side is minimal. For example, it is difficult to smile or bare one's teeth; the mouth is drawn to the unaffected (contralateral) side; and the person cannot wink, close the eyelid, or wrinkle the forehead on the affected side. Often, over time, the symptoms will disappear, but this may take weeks or months to occur.

Netters: auditory ossicles

1) malleus (head) 2) handle of malleus 3) stapes 4) base of stapes (footplate) 5) lenticular process of incus 6) incus * Comment: The 3 auditory ossicles reside in the middle ear, or tympanic cavity. They amplify sonic vibrations from the tympanic membrane and transmit them to the inner ear.The 3 ear ossicles are the malleus (hammer), incus (anvil), and stapes (stirrup). The handle of the malleus is fused with the medial aspect of the tympanic membrane; the head articulates with the incus. The incus articulates with the stapes, whose footplate is attached to the oval window. * Clinical: Two small muscles attach to the auditory ossicles; the tensor tympani muscle attaches to the malleus and the stapedius muscle to the stapes. These very small skeletal muscles dampen large vibrations resulting from excessively loud noises. Sensorineural hearing loss suggests a disorder of the internal ear involving the cochlea and/or the cochlear division of the vestibulocochlear nerve (CN VIII). Conductive hearing loss suggests a disorder of the external or middle ear, often involving the tympanic membrane (eardrum) and/or the middle ear ossicles.

Muscles Involved in Mastication Netter's

1) masseter muscle 2) parotid duct (cut) 3) buccinator muscle 4) temporalis muscle **Origin: Masseter muscle arises from the inferior border and medial surface of the zygomatic arch.**Insertion: Massester muscle attaches to the lateral surface of the mandible and lateral surface of the coronoid process.**Action: Masseter muscle closes the jaw by elevating the mandible.**Innervation: Mandibular division of the trigeminal nerve.**Comment: The masseter muscle is 1 of the 4 muscles of mastication. Some of its fibers also may protrude the mandible, and its deep fibers retract the mandible. Elevation of the jaw also is assisted by the actions of the temporalis and medial pterygoid muscles. Also shown in this image is the parotid duct as it pierces the buccinator muscle. This duct drains the parotid salivary gland. **Clinical: The muscles of mastication are derived embryologically from the 1st pharyngeal (branchial) arch and are innervated by the mandibular division of the trigeminal nerve (CN V3). The hearty spore of Clostridium tetani is commonly found in soil, dust, and feces and can enter the body through wounds, blisters, burns, skin ulcers, insect bites, and surgical procedures. If the individual is infected and unvaccinated, the toxin from the bacteria can destroy the inhibitory neurons of the brainstem and spinal cord and cause nuchal rigidity, trismus (lockjaw, a spasm of the masseter muscle), dysphagia, laryngospasm, and acute muscle spasms that can lead to death.

Cranial base: inferior view Netters

1) maxillary bone (incisive fossa; palatine process; zygomatic process) 2) zygomatic bone 3) sphenoid bone (medial plate; lateral plate; greater wing) 4) temporal bone (zygomatic process; mandibular fossa; styloid process; external acoustic meatus; mastoid process) 5) parietal bone 6) occipital bone (occipital condyle; basilar part; foramen magnum; external occipital protuberance) 7) vomer 8) palatine bone (horizontal plate) * Comment: Cranial bones (neurocranium) and facial bones (viscerocranium) contribute to the base of the skull. Key processes and foramina (openings or holes in the bone) associated with these bones can be seen in this inferior view.The largest foramen of the skull is the foramen magnum, the site where the spinal cord and brainstem (medulla oblongata) are continuous. * Clinical: Basilar fractures (fractures of the cranial base) may damage important neurovascular structures passing into or out of the cranium via foramina (openings). The internal carotid artery may be torn and the cranial nerves may be damaged. The dura mater may also be torn, resulting in leakage of the cerebrospinal fluid (CSF).At birth, the facial skeleton is small in comparison with the size of the head, but in the adult the facial skeleton forms about one-third of the cranium, with the greatest growth occurring in the maxillae, mandible, and nasal cavities.

Muscles Involved in Mastication anterior view Netters

1) medial pterygoid muscle 2) sphenomandibular ligament 3) levator veli palatini muscle (cut) 4) tensor veli palatini muscle (cut) 5) lateral pterygoid muscle 6) pterygoid hamulus **Origin: Medial pterygoid muscle arises from 2 slips. Its deep head arises from the medial surface of the lateral pterygoid plate and pyramidal process of the palatine bone. Its superficial head arises from the tuberosity of the maxilla.**Insertion: The fibers of the medial pterygoid muscle blend to attach to the medial surface of the ramus of the mandible, inferior to the mandibular foramen.**Action: Medial pterygoid muscle helps close the jaw by elevating the mandible. With the lateral pterygoids, the 2 medial pterygoids protrude the mandible. When 1 medial and 1 lateral pterygoid on the same side of the head act together, the mandible is protruded forward and to the opposite side. Alternating these movements moves the mandible from side to side in a grinding motion.**Innervation: Mandibular division of the trigeminal nerve.**Comment: The medial pterygoid is 1 of the 4 muscles of mastication. It acts with the temporalis and masseter muscles to close the jaw. The medial pterygoid and masseter muscles are important in biting, but all 3 muscles are necessary for biting and chewing with the molars. Also labeled are 2 muscles of the soft palate, 1 that tenses the palate and 1 that elevates the soft palate during swallowing.The muscles of mastication are derived embryologically from the 1st pharyngeal (branchial) arch and are innervated by the mandibular division of the trigeminal nerve (CN V3). **Clinical: Sometimes individuals clench their teeth and grind their molars while in deep sleep. This grinding action of the pterygoid muscles can erode the teeth, and people suffering from this malady should seek the attention of their health care specialist.

Netters Arteries of Oral and Pharyngeal Regions

1) middle meningeal artery 2) buccal artery 3) external carotid artery 4) superior thyroid artery 5) common carotid artery 6) subclavian artery 7) internal carotid artery 8) facial artery 9) maxillary artery 10) superficial temporal artery **Comment: Arteries of the oral and pharyngeal regions arise principally from branches of the external carotid artery. The external carotid gives rise to 8 branches: the superior thyroid artery, lingual artery, facial artery, ascending pharyngeal artery, occipital artery, posterior auricular artery, maxillary artery, and superficial temporal artery.The maxillary artery contributes many branches to the infratemporal region, nasal cavities, and muscles of mastication. Descriptively, the maxillary artery is divided into 3 parts (some of its branches are shown in this figure).The 1st (retromandibular) portion of this artery gives rise to branches supplying the tympanic cavity and membrane, dura mater, mandibular teeth and gums, ear, and chin. The 2nd (pterygoid) portion supplies the muscles of mastication and the buccinator. The 3rd (pterygopalatine) part supplies the maxillary teeth and gums, portions of the face, orbit, palate, auditory tube, superior pharynx, paranasal sinuses, and nasal cavity. **Clinical: Anastomoses among the branches of the facial and maxillary arteries are common and provide some collateral circulation to the face if 1 artery is compromised.

Muscles of pharynx posterior view Netters

1) middle pharyngeal constrictor muscle 2) internal carotid artery 3) stylopharyngeus muscle 4) glossopharyngeal nerve (CNIX) 5) superior cervical ganglion 6) vagus nerve (CNX) 7) thyroid and parathyroid glands 8) recurrent laryngeal nerve 9) internal jugular vein **Origin: Middle pharyngeal constrictor muscle arises from the stylohyoid ligament and the greater and lesser horns of the hyoid bone.**Insertion: The middle pharyngeal constrictor muscles from both sides wrap around and meet to attach to the median raphe of the pharynx. **Action: Middle pharyngeal constrictor muscle constricts the wall of the pharynx during swallowing. **Innervation: Pharyngeal plexus of the vagus nerve (CN X).**Comment: The middle pharyngeal constrictor lies largely behind the hyoid bone. The fibers of the superior and middle pharyngeal constrictors often blend together, but the demarcation point can be seen where the stylopharyngeus muscle intervenes. ** Clinical: Although the motor innervation of the pharyngeal constrictors is via the vagus nerve (CN X, pharyngeal plexus), the sensory innervation of all but the most superior part of the pharynx (the constrictor muscles and the mucosa lining the interior of the pharynx) is via the glossopharyngeal nerve (CN IX). Together, the fibers of CN IX and X form the pharyngeal plexus and function in concert with one another during swallowing.

Floor of Mouth Netters

1) mylohyoid muscle 2) hyoglossus muscle 3) digastric muscle (posterior belly) 4) stylohyoid muscle 5) digastric muscle (anterior belly) **Origin: Mylohyoid muscle arises from the mylohyoid line of the mandible.**Insertion: Mylohyoid muscle attaches to a median fibrous raphe and the body of the hyoid bone.**Action: Mylohyoid muscle elevates the hyoid bone and raises the floor of the mouth during swallowing, pushing the tongue upward as in swallowing or protrusion of the tongue. It also depresses the mandible.**Innervation: By the mylohyoid nerve, a branch of the mandibular division of the trigeminal.**Comment: The mylohyoids also can help depress the mandible or open the mouth. They are active in mastication, swallowing, sucking, and blowing. **Clinical: The mylohyoid and geniohyoid muscles form the floor of the mouth. Soft tissue injury in this area or fractures of the anterior mandible may result in significant bleeding in this area. These muscles are also important in multiple actions associated with the mouth.

Pterygopalatine Fossa netters

1) nasopalatine branch (septal branch) 2) pterygoid canal (behind ganglionic branches connecting maxillary nerve (CN V2) and pterygopalatine ganglion) 3) maxillary nerve (CN V2) 4) pterygopalatine ganglion 5) infraorbital nerve 6) posterior superior alveolar nerve 7) greater and lesser palatine nerves 8) lesser and greater palatine arteries 9) anterior and middle superior alveolar arteries 10) superficial temporal artery 11) maxillary artery 12) descending palatine artery 13) infraorbital artery 14) sphenopalatine artery **comment: Nerves are shown on 1 side and arteries on the other. This region is largely supplied by branches of the maxillary nerve (V2) and by arterial branches of the maxillary artery from the external carotid. The maxillary teeth and gums are supplied by the posterior, middle, and anterior superior alveolar neurovascular bundles. **Clinical: Midface fractures (Le Fort fractures) and/or blowout fractures of the orbital floor may damage the branches of the maxillary nerve, affecting not only sensory modalities related to the distribution of the nerve but also the parasympathetic postganglionic secretomotor fibers that join the branches of this nerve after they leave the pterygopalatine ganglion (site of the postganglionic parasympathetic neurons).

Autonomic Nerves in Head Netters

1) nerve (vidian) of pterygoid canal 2) deep petrosal nerve 3) greater petrosal nerve 4) otic ganglion 5) chorda tympani nerve 6) superior cervical ganglion 7) submandibular ganglion 8) pterygopalatine ganglion 9) ciliary ganglion **Comment: This schematic shows the 4 parasympathetic ganglia in the head. The ciliary ganglion receives preganglionic parasympathetic fibers from the oculomotor nerve. The otic ganglion receives preganglionic parasympathetic fibers that arise in the glossopharyngeal nerve. The pterygopalatine and submandibular ganglia receive preganglionic parasympathetics that originate in the facial nerve.Preganglionic sympathetic fibers arise from the upper thoracic spinal cord levels. They ascend the sympathetic trunk to synapse on postganglionic neurons in the superior cervical ganglion. Postganglionic sympathetic fibers travel on blood vessels or adjacent nerves (deep petrosal nerve) to reach their targets. These sympathetic postganglionic fibers are largely vasomotor in function. **Clinical: A unilateral lesion anywhere along the pathway of the preganglionic sympathetic axons, from the upper thoracic spinal cord levels (T1-T4) to the superior cervical ganglion (where they synapse), or beyond this ganglion (postganglionic axons), can result in ipsilateral Horner's syndrome. Its cardinal ipsilateral features are miosis (constricted pupil), slight ptosis (drooping of the eyelid due to loss of the superior tarsal muscle), anhidrosis (loss of sweat gland function), and flushing of the face (unopposed vasodilation).

Muscles of Larynx netters

1) oblique arytenoid muscles 2) transverse arytenoid muscles 3) epiglottis 4) aryepiglottic fold 5) cuneiform tubercle 6) corniculate tubercle 7) cricoid cartilage **Origin: Oblique and transverse arytenoid muscles arise from the arytenoid cartilages.**Insertion: The muscles attach to the opposite arytenoid cartilage. **Action: The muscles close the inlet of the larynx by adducting the arytenoid cartilages. This narrows the rima glottidis, the space between the vocal folds.**Innervation: Recurrent laryngeal nerve of the vagus.**Comment: Some muscle fibers of the oblique arytenoid continue superiorly as the aryepiglottic muscle. **Clinical: The vocal folds are controlled by the laryngeal muscles, all of which are innervated by the vagus nerve (CN X). During quiet respiration, the vocal folds are gently abducted to open the rima glottidis (space between the folds). In forced inspiration (taking a rapid, deep breath), the folds are maximally abducted by the posterior cricoarytenoid muscles, further enlarging the rima glottidis. During phonation, the folds are adducted and tensed to create a reed-like effect (similar to a reed musical instrument), causing vocal fold mucosal vibrations that produce sound that is then modified by the upper airway (pharynx, oral cavity, tongue, lips, nose, and paranasal sinuses). Closure of the rima glottidis occurs when holding your breath or when lifting something heavy (the Valsalva maneuver), and the folds are completely adducted.

Netters Muscles of Facial Expression: Lateral View

1) occipital belly of occipitofrontalis muscle 2) auricularis posterior muscle 3) auricularis superior muscle 4) auricularis anterior muscle 5) levator labii superioris alaeque nasi muscle 6) levator labii superioris muscle 7) zygomaticus minor muscle 8)zygomaticus major muscle *Origin: Occipital belly of the occipitofrontalis muscle arises from the lateral two-thirds of the superior nuchal line of the occipital bone and the mastoid process of the temporal bone. *Insertion: Occipital belly of occipitofrontalis muscle inserts into the epicranial aponeurosis (galea aponeurotica). *Action: The occipital and frontal bellies of the epicranial muscle act alternately to draw the skin of the scalp back or forward. Individually, the occipitalis draws the scalp backward. * Innervation: Terminal branches of the facial nerve; posterior auricular branches. **Comment: The extensive epicranial aponeurosis, which is called the galea aponeurotica, connects the frontal belly and occipital belly of the epicranial muscle.As a muscle of facial expression, this cutaneous muscle lies within the layers of the superficial fascia. These muscles vary from person to person, and they often blend together. **Clinical: All of the muscles of facial expression are derived embryologically from the 2nd pharyngeal (branchial) arch and are innervated by the terminal branches of the facial nerve (CN VII). Acute, unilateral facial palsy is the most common cause of facial muscle weakness and is called Bell's palsy. In Bell's palsy, paralysis of the occipitalis portion of the epicranius muscle would result in an inability to draw the skin of the scalp backward.

Nerves of Nasal Cavity Netters

1) olfactory bulb 2) lateral internal nasal branch of anterior ethmoidal nerve (CN V1) 3) palatine nerves (CNv2) (greater palatine nerve; lesser palatine nerve) 4) nasopalatine nerve (CNV2) 5) nerve (vidian) of pterygoid canal 6) deep petrosal nerve 7) greater petrosal nerve 8) pterygopalatine ganglion **Comment: Vessels of the nasal cavity receive innervation from sympathetic and, to a lesser extent, parasympathetic divisions of the autonomic nervous system.Sympathetic contributions travel in the deep petrosal nerve as postganglionic fibers that are largely vasomotor in function.Parasympathetic fibers travel in the facial nerve as preganglionics, course to the pterygopalatine ganglion in the greater petrosal and vidian nerves, and synapse in the pterygopalatine ganglion. Postganglionic fibers pass to the nasal mucosa, the hard and soft palates, and the mucosa of the paranasal sinuses. These fibers innervate mucous glands and microsalivary glands in the mucosa of the hard palate. **Clinical: Facial fractures may involve a fracture of the cribriform plate, which transmits the axons of the olfactory bipolar neurons. As a brain tract, CN I is covered by the 3 meningeal layers and contains cerebrospinal fluid (CSF) in its subarachnoid space around the olfactory bulb. A tear of the meninges can cause a leakage of CSF into the nasal cavity and provide a route of infection from the nose to the brain.

Infrahyoid and Suprahyoid Muscles Lateral view Netters

1) omohyoid muscle 2) sternohyoid muscle 3) thyrohyoid muscle 4) stylohyoid muscle 5) digastric muscle (posterior belly) 6) sternocleidomastoid muscle 7) scalenus muscle (posterior, medius and anterior) **Origin: The omohyoid muscle consists of an inferior and a superior belly. The inferior belly arises from the superior border of the scapula, near the suprascapular notch and passes to the intermediate tendon. The superior belly begins at the intermediate tendon and passes vertically. **Insertion: The superior belly passes vertically and inserts into the lower border of the hyoid bone. The inferior belly of the muscle inserts into the intermediate tendon deep to the sternocleidomastoid muscle.**Action: Omohyoid muscle depresses the hyoid bone after the bone has been elevated. It also retracts and steadies the hyoid bone. **Innervation: C1, C2, and C3 by a branch of the ansa cervicalis. **Comment: The omohyoid acts with the other infrahyoid muscles to depress the larynx and hyoid bone after these structures have been elevated during swallowing, speaking, or mastication (chewing).The omohyoid is an unusual "strap" muscle because it arises from the scapula in the shoulder region. **Clinical: The infrahyoid, or "strap," muscles are surrounded by an investing layer of cervical fascia that binds the neck muscles in a tight fascial sleeve. Swelling within this confined space can be painful and potentially damaging to adjacent structures. Immediately deep to this investing fascia is a "pretracheal space" anterior to the trachea and thyroid gland, which can provide a vertical conduit for the spread of infections.

Orientation of Nerves and Vessels of the Cranial Base Netters

1) optic nerve (CNII) 2) ciliary ganglion 3) maxillary nerve (CN V2) 4) artery and nerve of pterygoid canal 5) greater petrosal nerve 6) internal carotid artery (petrosal part) and venous plexus 7) facial nerve (CN VII) 8) internal carotid nerve and sympathetic nerve plexus 9) accessory nerve (CN XI) 10) internal jugular vein 11) internal carotid artery 12) superior cervical ganglion 13) descending palatine artery **Comment: The pathway of the internal carotid artery (ICA) is tortuous. It enters the skull via the carotid canal in the petrous portion of the temporal bone and then is directed anteromedially and superiorly across the foramen lacerum (closed by cartilage). The ICA then ascends into the cavernous sinus and, just inferior to the anterior clinoid process, makes a 180-degree turn to pass posteriorly to join in the cerebral arterial circle (of Willis). A venous plexus accompanies the ICA from the carotid canal to the cavernous sinus, as does a plexus of postganglionic sympathetic nerve fibers (called the deep petrosal nerve) from the superior cervical ganglion. The deep petrosal nerve joins the greater petrosal nerve (preganglionic parasympathetic fibers from CN VII) to form the nerve of the pterygoid canal (vidian nerve). ** Clinical: The close association of cranial nerves exiting the jugular foramen (CN IX, X, XI) and those associated with the cavernous sinus (CN III, IV, V1, V2, VI) may be involved in any trauma or pathology (e.g., tumor, abscess) that surrounds this confined bony region.

Muscles of Facial Expression: Lateral View Netter's

1) orbicularis oculi muscle 2) nasalis muscle (transverse and alar parts) 3) buccinator muscle *Origin: Orbicularis oculi muscle arises from the nasal portion of the frontal bone, the frontal process of the maxilla, the lacrimal bone, and the medial palpebral ligament.* Insertion: Orbicularis oculi muscle attaches to the skin of the eyelids, surrounds the bony orbit, and inserts into the superior and inferior tarsi medial to the lacrimal puncta. *Action: The orbicularis oculi muscle is a sphincter that closes the eyelids. Its palpebral portion closes the lids gently, as in blinking. The orbital portion closes the eyelids more forcibly. *Innervation: Terminal branches of the facial nerve; primarily the temporal and zygomatic branches. **Comment: The orbicularis oculi has 3 parts: an orbital part, which is thicker and surrounds the orbital margin; a palpebral part, which is thin and lies in the eyelids; and a lacrimal part.As a muscle of facial expression, this cutaneous muscle lies within the layers of the superficial fascia. **Clinical: All of the muscles of facial expression are derived embryologically from the 2nd pharyngeal (branchial) arch and are innervated by the terminal branches of the facial nerve (CN VII). Acute, unilateral facial palsy is the most common cause of facial muscle weakness and is called Bell's palsy. In Bell's palsy, paralysis of the orbicularis oculi would result in an inability to wink or close the eyelid ipsilaterally, with the potential for damage to the cornea because the tear film would not be evenly distributed across the cornea's surface.

Muscles of Facial Expression: Lateral View (mouth and neck) netters

1) orbicularis oris muscle 2) risorius muscle 3) platysma muscle **Origin: Orbicularis oris muscle fibers arise near the median plane of the maxilla above and from the mandible below and from the perioral skin. **Insertion: Fibers of the orbicularis oris muscle insert into the skin of the lips and into the mucous membrane beneath the lip. **Action: The orbicularis oris muscle acts primarily to close the lips. Its deep and oblique fibers pull the lips toward the teeth and alveolar arches. When all of its fibers act together, they can protrude the lips. **Innervation: Terminal branches of the facial nerve; primarily the buccal and mandibular branches. **Comment: A major portion of the orbicularis oris muscle is derived from the buccinator and blends with other facial muscles around the oral cavity. This muscle is especially important in speech because it alters the shape of the mouth.As a muscle of facial expression, this cutaneous muscle lies within the layers of the superficial fascia. **Clinical: All of the muscles of facial expression are derived embryologically from the 2nd pharyngeal (branchial) arch and are innervated by the terminal branches of the facial nerve (CN VII). Acute, unilateral facial palsy is the most common cause of facial muscle weakness and is called Bell's palsy. In Bell's palsy, paralysis of the orbicularis oris would result in an inability to ipsilaterally purse the lips, as in kissing someone, or protrude the lips.

Lacrimal Apparatus Netters

1) orbital part of lacrimal gland 2) plica semilunaris and lacrimal lake 3) lacrimal caruncle 4) inferior lacrimal papilla and punctum 5) inferior nasal meatus 6) nasolacrimal duct 7) lacrimal sac 8) lacrimal canaliculi **Comment: The lacrimal apparatus consists of the lacrimal glands, which secrete tears, and a system of collection ducts. Lacrimal ducts convey tears from the glands to the conjunctival sac, and the lacrimal canaliculi drain them into the lacrimal sac. Next, tears drain down the nasolacrimal duct and empty into the inferior nasal meatus behind the inferior nasal concha.Production of tears is under parasympathetic autonomic control exerted by nerve fibers that originate in the facial nerve (CN VII) and ultimately reach the glands via the lacrimal nerve, a branch of the ophthalmic division of the trigeminal nerve.The human plica semilunaris is our remnant of the nictitating membrane (a 3rd eyelid that is transparent), seen in many other vertebrates, especially birds, reptiles, and some mammals. ** Clinical: The tears contain albumins, lactoferrin, lysozyme, lipids, metabolites, and electrolytes and provide a protective layer of fluid that helps keep the cornea moist and protected from infection. Dry eye (insufficient tear production) is not uncommon and can be treated with lubricating moisturizing eyedrops or systemically with prescription medications.

Label skull bones: lateral view Netters

1) parietal bone 2) coronal suture 3) sphenoid bone 4) lacrimal bone 5) maxillary bone (frontal process; alveolar process) 6) zygomatic bone 7) occipital bone (external occipital protuberance) 8) lambdoid suture 9) temporal bone (squamous part; zygomatic process; external acoustic meatus; mastoid process) The coronal suture lies between the frontal bone and the paired parietal bones. The lambdoid suture lies between the paired parietal bones and the occipital bone.The pterion is the site of union of the frontal, parietal, sphenoid, and temporal bones. A blow to the head or a skull fracture in this region is dangerous because the bone at this site is thin, and the MIDDLE MENINGEAL ARTER, supplying the dural covering of the brain, lies just deep to this area. The asterion is the site of union of the temporal, parietal, and occipital bones. Clinical: Skull fractures may be classified as: A) Linear: fracture with a distinct fracture line B) Comminuted: fracture with multiple bone fragments (fragments are depressed if driven inwardly and can tear the dura mater) C) Diastasic: fracture along a suture line D) Basilar: fracture of the base of the skull. A blow to the pterion may damage the middle meningeal artery (or one of its branches), which lies just deep to this thin area of bone, causing an epidural (extradural) hematoma (bleeding between the periosteal layer of dura and the overlying bone).

Superficial Face and Parotid Gland Netters

1) parotid gland 2) main trunk of facial nerve emerging from stylomastoid foramen 3) sternocleidomastoid muscle 4) external jugular vein 5) temporal branches of facial nerve 6) parotid duct 7) masseter muscle 8) facial artery and vein 9) cervical branch of facial nerve (CN VII) **Comment: The parotid salivary gland is the largest of the 3 paired salivary glands.The parotid duct passes horizontally from the gland, pierces the buccinator muscle, and enters the oral cavity opposite the 2nd maxillary molar tooth.The facial nerve (CN VII) exits through the stylomastoid foramen, passes through the parotid gland, and distributes its 5 terminal branches over the face. These are the temporal, zygomatic, buccal, marginal mandibular, and cervical branches. These nerves innervate the muscles of facial expression. **Clinical: Surgery involving the parotid gland (tumor resection) or trauma to this region of the face places the terminal motor branches of the facial nerve (CN VII) in jeopardy, which could result in paralysis or weakness to 1 or more of the facial muscles.A stone (calculus) may occlude the parotid (Stensen's) duct, necessitating its removal.The parotid gland is innervated by the glossopharyngeal nerve (CN IX) via preganglionic parasympathetic fibers that course to the otic ganglion via the lesser petrosal nerve, synapse in the ganglion, and send postganglionic fibers to the gland via the auriculotemporal branch of CN V3.

Pharynx median section label

1) pharyngeal opening of pharyngotympanic (auditory tube) 2) pharyngeal tonsil 3) anterior arch of atlas (c1 vertebra) 4) pharyngeal constrictor muscle 5) retropharyngeal space 6) vertebral bodies 7) trachea (top arrow) and oesophagus 8) transverse arytenoid muscle 9) laryngopharynx (top arrow) and laryngeal inlet (aditus) 10) epiglottis 11) palatine tonsil, body of tongue, oropharynx (top to bottom) 12) hard palate 13) nasopharynx (top arrow), soft palate

Muscles of Facial Expression: Anterior View Netters

1) platysma muscle (partially cut to review deep muscles) 2) mylohyoid muscle 3) thyrohyoid muscle 4) omohyoid muscle (superior belly) 5) sternohyoid muscle 6) sterhothyroid muscle 7) sternocleidomastoid muscle (sternal and clavicular heads) **Origin: Platysma muscle arises from the superficial fascia covering the superior portions of the pectoralis major and deltoid muscles.**Insertion: Platysma muscle ascends over the clavicle and is directed medially to insert into the mandible below the oblique line. Other portions of the muscle insert into the skin and subcutaneous tissue of the lower portion of the face.**Action: Platysma muscle draws the lower lip and corner of the mouth inferolaterally and partially opens the mouth, as during an expression of surprise. When all the fibers act together, the skin over the clavicle and lower neck is wrinkled and drawn upward toward the mandible.**Innervation: Terminal branches of the facial nerve; cervical branch.**Comment: As a muscle of facial expression, the cutaneous platysma muscle lies within the layers of the superficial fascia. **Clinical: All of the muscles of facial expression are derived embryologically from the 2nd pharyngeal (branchial) arch and are innervated by the terminal branches of the facial nerve (CN VII). Acute, unilateral facial palsy is the most common cause of facial muscle weakness and is called Bell's palsy. In Bell's palsy, paralysis of the platysma muscle would result in an inability to ipsilaterally draw the corner of the lip downward and tense the skin of the neck between the clavicle and the mandible. The platysma also covers the anterior muscles of the neck, as shown here.

Netters: external craniocervical ligaments

1) posterior atlantooccipital membrane 2) capsule of atlantooccipital joint 3) transverse process of atlas (C1) 4) capsule of lateral atlantoaxial joint 5) ligamenta flava 6) capsule of atlantooccipital joint 7) posterior atlantooccipital membrane 8) ligamenta flava 9) nuchal ligament 10) spinous process of C7 vertebra (vertebra prominens) 11) spinous process of T1 vertebra 12) T1 vertebra 13) vertebral artery 14) anterior longitudinal ligament * Comment: The atlantooccipital joint, on each side, is covered with an articular capsule and posteriorly reinforced by the posterior atlantooccipital membrane. It permits flexion and extension (the action of nodding one's head up and down to signify "yes").The ligamentum nuchae is a strong median fibrous septum. It is an extension of the thickened supraspinous ligaments that arise from the spinous process of C7 and extend to the external occipital protuberance. * Clinical: While there are usually 7 cervical vertebrae, fusion of adjacent cervical vertebrae can occur. Most commonly, this fusion in the cervical region is seen between C1 and C2 (the atlas and axis) or between C5 and C6. Trauma to the upper cervical region can result in the axis being displaced anteriorly over the C3 vertebra, causing injury to the spinal cord and quadriplegia (loss of movement of the upper and lower limbs bilaterally).

Veins of Oral and Pharyngeal Regions Netters

1) pterygoid plexus 2) superior laryngeal vein 3) middle thyroid vein 4) inferior thyroid veins 5) subclavian vein 6) internal jugular vein 7) common trunk for facial, retromandibular, and lingual veins 8) external jugular vein (cut) 9) retromandibular vein 10) superficial temporal vein and artery **Comment: Veins of the facial, oral, and pharyngeal regions are largely tributaries that ultimately collect in the internal jugular vein. In the infratemporal region, a pterygoid plexus of veins communicates with the cavernous sinus and veins of the orbit and oral cavity. Many of the veins of this region have the same names as their corresponding arteries. Key veins are as follows: The retromandibular vein receives tributaries from the temporal and infratemporal regions (pterygoid plexus), nasal cavity, pharynx, and oral cavity. The internal jugular vein drains the brain, face, thyroid gland, and neck. The external jugular vein drains the superficial neck, lower neck and shoulder, and upper back (often communicates with the retromandibular vein). **Clinical: These veins generally do not possess valves and therefore provide avenues for the spread of infection throughout the head and neck region. The pterygoid plexus of veins has connections with the ophthalmic veins (and to the cavernous sinus via these veins), facial veins, and superficial temporal veins and their small tributaries, which also pass through the skull as emissary veins to drain into the dural venous sinuses.

Netters prevertebral Muscles

1) scalenus muscles (anterior, medius, posterior) **Origin (Superior Attachment): The scalenus anterior arises from the anterior tubercles of the transverse processes of C3-C6 vertebrae. The scalenus medius and scalenus posterior arise from the posterior tubercles of the transverse processes of C2-C7 (middle) and C4-C6 (posterior). **Insertion (Inferior Attachment): The scalenus anterior attaches to the scalene tubercle of the 1st rib. The scalenus medius attaches to the superior surface of the 1st rib. The scalenus posterior attaches to the external border of the 2nd rib.**Action: The scalenus anterior and scalenus medius elevate the 1st rib. When that rib is fixed, they also flex the neck forward and laterally and rotate it to the opposite side. The scalenus posterior raises the 2nd rib and flexes and slightly rotates the neck.**Innervation: The scalenus anterior is innervated by C5-C7 anterior rami; the scalenus medius, by C3-C8 anterior rami; and the scalenus posterior, by anterior rami of C6-C8. **Comment: The scalenus muscles are often called lateral vertebral muscles. They form a large portion of the floor of the posterior cervical triangle. Components of the brachial plexus can be seen emerging between the scalenus anterior and scalenus medius muscles. **Clinical: The scalenus muscles are accessory muscles of respiration and help elevate the first 2 ribs during deep or labored breathing. They form a portion of the floor of the posterior cervical triangle and are crossed by the accessory nerve (CN XI) as it passes between the sternocleidomastoid and trapezius muscles. The phrenic nerve (C3-C5) is observed on the anterior surface of the scalenus anterior muscle; it courses inferiorly toward the diaphragm, which it innervates. Trauma to the neck can damage these nerves.

label this pharynx

1) soft palate 2) uvula 3) root of tongue 4) epiglottis 5) laryngeal inlet (aditus) 6) piriform fossa 7) oesophagus 8) laryngopharynx 9) oropharynx 10) nasopharynx

Label skull: midsagittal section Netters

1) sphenoid bone (greater wring; lesser wing; sella turcica; sphenoidal sinus) 2) frontal bone (frontal sinus) 3) ethmoid bone (perpendicular plate) 4) maxillary bone (incisive canal; palatine process) 5) Vomer 6) Palatine bone 7) occipital bone 8) temporal bone (squamous part; petrous part) 9) parietal bone

Netters Maxillary Artery

1) sphenopalatine artery 2) posterior superior alveolar artery 3) septal branches of sphenopalatine artery 4) left and right greater palatine arteries 5) descending palatine artery in pterygopalatine fossa 6) inferior alveolar artery 7) middle meningeal artery 8) deep temporal arteries and veins **Comment: The maxillary artery is 1 of the 2 terminal branches of the external carotid artery. It passes superficially or deeply to the lateral pterygoid muscle and courses medially in the infratemporal fossa. Descriptively, it is divided into 3 parts.The 1st (retromandibular) portion of this artery gives rise to branches supplying the tympanic cavity and membrane, dura mater, mandibular teeth and gums, ear, and chin. The 2nd (pterygoid) portion supplies the muscles of mastication and the buccinator. The 3rd (pterygopalatine) part supplies the maxillary teeth and gums, portions of the face, orbit, palate, auditory tube, superior pharynx, paranasal sinuses, and nasal cavity. **Clinical: A nosebleed, or epistaxis, is a common occurrence and often involves the richly vascularized region of the vestibule and the anteroinferior aspect of the nasal septum (Kiesselbach's area). Many of these small nasal arteries and arterioles are branches of the maxillary artery and facial artery (lateral nasal and septal branches).

Muscles of Neck: Anterior View Netters

1) sternocleidomastoid muscle 2) digastric muscle (posterior belly) 3) mylohyoid muscle 4) digastric muscle (anterior belly) 5) stylohyoid muscle 6) platysma muscle (cut) **Origin: (Inferior Attachment) The sternocleidomastoid muscle has 2 heads of origin. The sternal head arises from the anterior surface of the manubrium of the sternum. The clavicular head arises from the superior surface of the medial third of the clavicle. **Insertion: (Superior Attachment) Sternocleidomastoid muscle attaches to the lateral surface of the mastoid process of the temporal bone and the lateral half of the superior nuchal line. **Action: Sternocleidomastoid muscle tilts the head to 1 side, flexes the neck, and rotates the neck so the face points superiorly to the opposite side. When the muscles of both sides act together, they flex the neck. **Innervation: Accessory nerve (CN XI and C2 and C3). **Comment: When the head is fixed during forced inspiration, the 2 sternocleidomastoid muscles acting together can help elevate the thorax. The sternocleidomastoid is 1 of 2 muscles innervated by the accessory nerve. Although the accessory nerve is classified as a cranial nerve, it does not possess any fibers originating from the brainstem. Its nerve fibers originate in the upper cervical spinal cord, so its classification as a "true" cranial nerve is problematic. ** Clinical: The sternocleidomastoid (SCM) is innervated by the accessory nerve (CN XI). This nerve is susceptible to injury where it crosses the posterior cervical triangle between the SCM muscle and the trapezius muscle. CN XI innervates both of these muscles.Congenital torticollis is a contraction of the SCM that can result from a fibrous tissue tumor that develops in the muscle (wry neck). A twisting of the neck occurs such that the head is tilted toward the lesioned side (ipsilaterally) and the face is turned contralaterally.Spasmodic torticollis occurs more commonly in adults and can affect the SCM or several other cervical muscles.

Infrahyoid and Suprahyoid Muscles (netters)

1) sternohyoid muscle 2) omohyoid muscle (superior belly) 3) omohyoid muscle (inferior belly) 4) thyrohyoid muscle **Origin: Sternohyoid muscle arises from manubrium of the sternum and medial portion of the clavicle. **Insertion: Sternohyoid muscle inserts on inferior border of the body of the hyoid bone. **Action: Sternohyoid muscle depresses the hyoid bone after swallowing (the hyoid bone is elevated when swallowing). **Innervation: C1, C2, and C3 from the ansa cervicalis. **Comment: The sternohyoid is part of the group of infrahyoid muscles. These muscles are often referred to as "strap" muscles because they are long and narrow. They are involved in movements of the hyoid bone and thyroid cartilage during swallowing, speaking, and mastication (chewing). **Clinical: The infrahyoid, or "strap," muscles are surrounded by an investing layer of cervical fascia that binds the neck muscles in a tight fascial sleeve. Swelling within this confined space can be painful and potentially damaging to adjacent structures. Immediately deep to this investing fascia is a "pretracheal space" anterior to the trachea and thyroid gland, which can provide a vertical conduit for the spread of infections.

Infrahyoid and Suprahyoid Muscles Netters

1) sternothyroid muscle 2) thyrohyoid membrane 3) hyoid bone 4) thyroid cartilage 5) cricoid cartilage 6) thyroid gland 7) trachea **Origin: Sternothyroid muscle arises from the posterior surface of the manubrium of the sternum and the edge of the 1st costal cartilage.**Insertion: Sternothyroid muscle attaches to the oblique line of the lamina of the thyroid cartilage. **Action: Sternothyroid muscle depresses the larynx after the larynx has been elevated for swallowing.**Innervation: C2 and C3 from the ansa cervicalis. **Comment: The sternothyroid is part of the group of infrahyoid muscles. Because they are long and narrow, these muscles are often referred to as "strap" muscles. They are involved in movements of the hyoid bone and thyroid cartilage during swallowing, speaking, and mastication (chewing). **Clinical : The infrahyoid, or "strap," muscles are surrounded by an investing layer of cervical fascia that binds the neck muscles in a tight fascial sleeve. Swelling within this confined space can be painful and potentially damaging to adjacent structures. Immediately deep to this investing fascia is a "pretracheal space" anterior to the trachea and thyroid gland, which can provide a vertical conduit for the spread of infections.

Tongue (deeper) Netter's

1) styloglossus muscle 2) lingual nerve 3) submandibular ganglion 4) submandibular duct 5) geniohyoid muscle 6) hypoglossal nerve (CNXII) 7) lingual vein 8) internal jugular vein 9) external carotid artery 10) lingual artery **Origin: Styloglossus muscle arises from the styloid process and stylohyoid ligament. **Insertion: Styloglossus muscle attaches to the lateral side of the tongue. Some fibers interdigitate with fibers of the hyoglossus muscle. **Action: Styloglossus muscle retracts the tongue and draws it up during swallowing.Innervation: Hypoglossal nerve (CN XII). **Comment: The styloglossus is 1 of the 3 extrinsic muscles of the tongue. Of the 3 styloid muscles, the styloglossus muscle is the smallest. All are innervated by the hypoglossal nerve.All of the muscles with "glossus" in their names are innervated by the hypoglossal nerve except the palatoglossus muscle, which is a muscle of both the tongue and soft palate and is innervated by the vagus nerve.Three muscles arise from the styloid process: the styloglossus, the stylohyoid, and the stylopharyngeus muscles. Each is innervated by a different cranial nerve. ** Clinical: The styloglossus is important in swallowing because it pushes the bolus of chewed food up against the hard palate and backward into the oropharynx.

Suprahyoid Muscles Netters

1) stylohyoid muscle 2) thyrohyoid muscle 3) omohyoid muscle (superior belly) 4) sternohyoid muscle 5) fibrous loop of intermediate digastric tendon **Origin: Stylohyoid muscle arises from the styloid process of the temporal bone. **Insertion: Stylohyoid muscle attaches to the body of the hyoid bone.**Action: Stylohyoid muscle elevates and retracts the hyoid bone in an action that elongates the floor of the mouth. **Innervation: Facial nerve.**Comment: The stylohyoid muscle is perforated near its insertion by the tendon of the 2 bellies of the digastric muscle.The stylohyoid is 1 of the 3 muscles arising from the styloid process, each innervated by a different cranial nerve. The other 2 muscles are the stylopharyngeus (CN IX) and the styloglossus (CN XII). **Clinical: The stylohyoid is 1 of several muscles that help stabilize the hyoid bone, which is important in movements of the tongue and in swallowing, speaking, and mastication (chewing). If this process is compromised, these movements become more difficult and/or painful to execute.

Muscles of Pharynx Posterior view Netters

1) stylopharyngeus muscle 2) CNXII 3) CN XI 4) CN X 5) sympathetic trunk **Origin: Stylopharyngeus muscle arises from the styloid process of the temporal bone. **Insertion: Stylopharyngeus muscle attaches to the posterior and superior margins of the thyroid cartilage.**Action: Stylopharyngeus muscle elevates the pharynx and larynx during swallowing and speaking.**Innervation: Glossopharyngeal nerve (CN IX).**Comment: The stylopharyngeus muscle passes between the superior and middle pharyngeal constrictors. The stylopharyngeus is 1 of 3 muscles arising from the styloid process of the temporal bone (the others are the styloglossus and stylohyoid). Each muscle is innervated by a different cranial nerve and arises from a different embryonic branchial arch.The stylopharyngeus arises embryologically from the 3rd pharyngeal (branchial) arch and is the only muscle innervated by the glossopharyngeal nerve. **Clinical: A lesion to the motor fibers of CN IX that innervate the stylopharyngeus muscle can lead to pain when the patient initiates swallowing.

Tongue and related structures pic

1) submandibular ganglion 2) lingual nerve 3) styloglossus muscle 4) palatoglossus muscle 5) lingual artery 6) hyoglossus 7) hypoglossal nerve 8) hyoid bone 9) geniohyoid muscle

Netters Carotid Arteries

1) superficial temporal artery 2) occipital artery 3) internal carotid artery 4) external carotid artery 5) common carotid artery 6) superior thyroid artery and superior laryngeal branch 7) ascending pharyngeal artery 8) lingual artery 9) facial artery 10) posterior auriciular artery 11) maxillary artery **Comment: The common carotid artery ascends in the neck in the carotid sheath. At about the level of the superior border of the thyroid cartilage it divides into the internal carotid artery, which passes into the cranium, and the external carotid artery, which supplies more superficial structures lying outside the skull. The external carotid artery gives rise to 8 branches.These 8 branches supply much of the blood to the head outside of the cranium, although several branches also ultimately enter the cranial regions (meningeal and auricular branches of the maxillary artery, 1 of the terminal branches of the external carotid). **Clinical: The branches of the external carotid arteries anastomose across the midline neck (superior thyroid arteries) and the face to provide collateral circulation should the arterial blood supply be compromised by occlusion or lacerated in trauma.The small branches of the superficial temporal artery supply the scalp, which bleeds profusely when cut because the small arteries are held open (rather than retracted into the subcutaneous tissue) by the tough connective tissue lying just beneath the skin (epidermis and dermis).

Parathyroid and Thyroid Glands: Posterior View Netters

1) superior laryngeal nerve 2) superior thyroid artery 3) superior parathyroid gland 4) inferior parathyroid gland 5) thyrocervical trunk 6) recurrent laryngeal nerve 7) inferior thyroid artery 8) right lobe of thyroid gland **Comment: Because of their embryonic development, the parathyroid glands, especially the inferior pair, may vary in location. Although most people have 4 parathyroid glands, it is not uncommon to have more than 4, with some variability in location.During neck surgery, it is important to note the location of the recurrent laryngeal nerves. Both recurrent nerves typically ascend in the tracheoesophageal groove and are in close relationship to the right and left lobes of the thyroid gland. The right recurrent laryngeal nerve loops around the right subclavian artery, whereas the left recurrent laryngeal nerve loops around the arch of the aorta. **Clinical: The most common type of hyperthyroidism in patients younger than 40 years old is Graves' disease. The excess release of thyroid hormone upregulates tissue metabolism and leads to symptoms indicating increased metabolism (excitability, flushing, warm skin, increased heart rate, shortness of breath, tremor, exophthalmos, myxedema, goiter).Primary hyperparathyroidism leads to the secretion of excess parathyroid hormone that increases plasma calcium levels at the expense of calcium deposition in the bones (weakens the bones). Normally, about 99% of the body's calcium is stored in bone.

Netters Muscles of Pharynx

1) superior pharyngeal constrictor muscle 2) stylopharyngeus muscle 3) medial pterygoid muscle 4) stylohyoid muscle 5) digastric muscle (posterior belly) 6) levator veli palatini muscle 7) palatopharyngeus muscle ** Origin: The broad superior pharyngeal constrictor muscle arises from the pterygoid hamulus, pterygomandibular raphe, posterior portion of the mylohyoid line of the mandible, and side of the tongue.**Insertion: The superior pharyngeal constrictor muscles from each side meet and attach to the median raphe of the pharynx and pharyngeal tubercle of the occipital bone. **Action: Superior pharyngeal constrictor muscle constricts the wall of the upper pharynx during swallowing.**Innervation: Pharyngeal plexus of the vagus nerve (CN X). **Comment: The 3 pharyngeal constrictors help move food down the pharynx and into the esophagus. To accomplish this, these muscles contract serially from superior to inferior to move a bolus of food from the oropharynx and laryngopharynx into the proximal esophagus.The superior constrictor lies largely behind the mandible. **Clinical: Although the motor innervation of the pharyngeal constrictors is via the vagus nerve (CN X), the sensory innervation of all but the most superior part of the pharynx (the constrictor muscles and the mucosa lining the interior of the pharynx) is via the glossopharyngeal nerve (CN IX). Together, the fibers of CN IX and X form the pharyngeal plexus and function in concert with one another during swallowing.

Extrinsic Eye Muscles Netters

1) superior rectus muscle 2) medial rectus muscle 3) inferior rectus muscle 4) superior oblique muscle 5) lateral rectus muscle 6) inferior oblique muscle 7) lateral rectus muscle (cut) **Origin: The 4 rectus muscles and the superior oblique arise from a common tendinous ring (anulus of Zinn) on the body of the sphenoid bone. The inferior oblique arises from the floor of the orbit, lateral to the nasolacrimal fossa.**Insertion: The 4 rectus muscles insert into the sclera, just posterior to the cornea. The superior oblique muscle passes forward, and its tendon passes through a fibrous ring (trochlea) and inserts into the sclera deep to the superior rectus muscle. The inferior oblique inserts into the sclera deep to the lateral rectus muscle.**Actions: In clinical testing, when the eye is abducted, the superior rectus elevates the globe and the inferior rectus depresses it. When the eye is adducted, the superior oblique depresses the globe and the inferior oblique elevates it. The medial rectus is a pure adductor, whereas the lateral rectus is a pure abductor. The anatomic actions differ from the actions tested for clinical evaluation of the muscles.**Innervation: The lateral rectus is innervated by the abducens nerve (CN VI); the superior oblique is innervated by the trochlear nerve (CN IV). All the other rectus muscles and the inferior oblique are innervated by the oculomotor nerve (CN III). **Clinical: Ipsilateral abducent nerve palsy will result in the patient's inability to fully abduct the ipsilateral eye. Ipsilateral trochlear nerve palsy will result in the patient's inability to adduct and depress the ipsilateral eye, resulting in diplopia (double vision) when going down stairs. Third nerve palsy will result in ptosis, a dilated pupil, and an inability to adduct the eye (at rest, the affected eye will be directed down and out).

Cutaneous Nerves of Head and Neck Netters

1) supraorbital nerve 2) infraorbital nerve 3) mental nerve 4) buccal nerve 5) auriculotemporal nerve 6) supraclavicular nerves (C3,4) 7) great auricular nerve (C2,3) 8) greater occipital nerve **Comment: Cutaneous innervation of the face is by the 3 divisions of the trigeminal nerve (CN V). The ophthalmic division is represented largely by the supraorbital and supratrochlear nerves. The maxillary division is represented by the infraorbital and zygomaticotemporal nerves. The mandibular division is represented largely by the mental, buccal, and auriculotemporal nerves.The skin on the back of the scalp receives cutaneous innervation from the greater occipital nerve (dorsal ramus of C2); the skin on the back of the neck receives innervation from dorsal rami of cervical nerves.The 1st cervical nerve (C1) has few if any sensory nerve fibers from the skin, so it is usually not shown on dermatome charts. **Clinical: The sensory innervation of the face is via the 3 divisions of CN V. Trauma anywhere along the pathway of the nerve, including that on the face itself (e.g., facial lacerations), can lead to loss of sensation. The innervation of the muscles of facial expression will not be affected unless a laceration also damages the terminal branches of the facial nerve.

Muscles Involved in Mastication Netters

1) temporalis muscle 2) insertion of masseter muscle (cut away) 3) buccinator muscle 4) orbicularis oris muscle **Origin: Temporalis muscle arises from the floor of the temporal fossa and the deep surface of the temporal fascia.**Insertion: Temporalis muscle attaches to the tip and medial surface of the coronoid process and anterior border of the ramus of the mandible.**Action: Temporalis muscle elevates the mandible and closes the jaw. Its posterior fibers retract the mandible (retrusion). Elevation of the jaw also is assisted by the actions of the masseter and medial pterygoid muscles. The masseter muscle is shown cut away in this image.**Innervation: Mandibular division of the trigeminal nerve.**Comment: The temporalis is 1 of the 4 muscles of mastication. It is a broad, radiating muscle whose contractions can be seen during chewing. The muscles of mastication are derived embryologically from the 1st pharyngeal (branchial) arch and are innervated by the mandibular division of the trigeminal nerve (CN V3). Also shown in this image are 2 of the muscles of facial expression, the buccinator and orbicularis oris muscles. ** Clinical: Tension headache can be muscular in origin. Tensing the temporalis muscle, for example (clenching the teeth), can lead to this type of headache.

Roof of Mouth: Netters

1) tensor veli palatini muscle 2) basilar part of occipital bone 3) cartilaginous part of auditory tube (eustachian) 4) superior pharyngeal constrictor muscle *Origin: Tensor veli palatini muscle arises from the scaphoid fossa of the medial pterygoid plate, spine of the sphenoid bone, and cartilage of the auditory tube. **Insertion: Tensor veli palatini muscle attaches to the palatine aponeurosis of the soft palate and the palatine crest on the horizontal plate of the palatine bone. **Action: Tensor veli palatini muscle tenses the soft palate and, by contracting, opens the auditory tube during swallowing and yawning to equalize pressure in the middle ear. **Innervation: Mandibular division of the trigeminal nerve.**Comment: The tensor veli palatini muscle tenses the fibers of the soft palate so that the levator veli palatini muscle can act on them. **Clinical: The tensor not only tenses the soft palate during elevation by the levator veli palatini but also opens the auditory (pharyngotympanic, eustachian) tube during swallowing and yawning. This helps equalize the pressure in the middle ear and explains why chewing gum, swallowing, or yawning can relieve the pressure and pain in the middle ear when landing in an airplane.

Infrahyoid and Suprahyoid Muscles vessels netters

1) thyrohyoid muscle 2) common carotid artery 3) sternohyoid muscle 4) ansa cervicalis (C1-C3 of cervical plexus) 5) internal jugular vein 6) external jugular vein 7) anterior jugular vein **Origin: Thyrohyoid muscle arises from the oblique line of the lamina of the thyroid cartilage. **Insertion: Thyrohyoid muscle attaches to the inferior border of the body and the greater horn of the hyoid bone.**Action: Thyrohyoid muscle depresses the hyoid bone and, if the hyoid bone is fixed, draws the thyroid cartilage superiorly. **Innervation: C1 via the hypoglossal nerve (CN XII). **Comment: The thyrohyoid muscle is supplied by fibers of the 1st cervical nerve that happen to travel with the last cranial, or hypoglossal, nerve (CN XII).The thyrohyoid muscle is also 1 of the infrahyoid, or "strap," muscles. **Clinical: Trauma to the neck may damage the ansa cervicalis (C1-C3) and its branches, leading to paralysis of the infrahyoid and suprahyoid muscles. Because these muscles are critical in the process of swallowing, dysphagia (difficulty in swallowing) may ensue.

Netters nerves of Orbit

1) trochlear nerve (CN IV) 2) ophthalmic nerve (CN V1) 3) optic nerve (CN II) 4) oculomotor nerve (CN III) 5) abducens nerve (CN VI) 6) trigeminal (semilunar) ganglion 7) frontal nerve 8) lacrimal nerve 9) supraorbital nerve **Comment: The sensory innervation to the orbit arises from the ophthalmic division of the trigeminal nerve. The major nerves of this division include the nasociliary, frontal, and lacrimal nerves. The sensory nerve cell bodies reside in the trigeminal (semilunar) ganglion.The motor innervation of the extraocular muscles comes from the oculomotor, trochlear, and abducens nerves.The optic nerve leaves the orbit via the optic canal. CN III, CN IV, CN V1, and CN VI traverse the superior orbital fissure. **Clinical: The ophthalmic division of the trigeminal nerve (CN V1) is the smallest division of CN V. In addition to its sensory role and, similar to the other 2 divisions of the trigeminal nerve, this division carries autonomic fibers to the eyeball via its nasociliary nerve and connections to the ciliary ganglion (long and short ciliary nerves). Additionally, it carries parasympathetics from the facial nerve (CN VII) that join the lacrimal branch and innervate the lacrimal glands, which produce tears that moisten the cornea of the eyeball. Orbital trauma or infections in this confined compartment may affect these important autonomic pathways.

Roof of Mouth anterior view Netters

1) uvular muscle 2) palatopharyngeus muscle 3) palatoglossus muscle 4) superior pharyngeal constrictor muscle 5) pterygomandibular raphe 6) buccinator muscle **Comment: Interdigitating fibers of the levator veli palatini muscle make up most of the soft palate, along with the little uvular muscle.The palatoglossal and palatopharyngeal arches contain small slips of muscle (with the same names as the arches) beneath their mucosal surfaces. These thin muscle slips are innervated by the vagus nerve. The palatine tonsil is nestled in the palatine fossa, between these 2 folds.The buccinator muscle lies deep to the oral mucosa of the cheek and helps keep food between the molars. This muscle of facial expression is innervated by the facial nerve (CN VII).Numerous minor salivary glands populate the mucosa lining the hard palate. **Clinical: If the facial nerve (CN VII) is damaged or dysfunctional, as in Bell's palsy, the buccinator muscle will be paralyzed and the patient will be unable to suck the cheeks inwardly. If the parasympathetic fibers of the facial nerve are damaged (they travel in the lingual nerve of CN V3), 2 of the 3 major salivary glands will be denervated (the submandibular and sublingual glands), as will the numerous minor salivary glands, also supplied by facial parasympathetic nerves. Consequently, the oral mucosa will appear drier than normal.

Subclavian Artery Netters

1) vertebral artery 2) costocervical trunk 3) supreme intercostal artery 4) internal thoracic artery 5) suprascapular artery 6) thyrocervical trunk 7) common carotid artery 8) transverse cervical artery 9) inferior thyroid artery **Comment: The subclavian artery is divided into 3 parts relative to the anterior scalenus muscle. The 1st part is medial to the muscle, the 2nd is behind the muscle, and the 3rd is lateral. Branches of the subclavian artery include the vertebral artery and internal thoracic (mammary) artery, thyrocervical and costocervical trunks, and dorsal scapular artery.The vertebral artery ascends through the C6-T1 transverse foramina and enters the foramen magnum. The internal thoracic descends parasternally. The thyrocervical trunk supplies the thyroid gland (inferior thyroid artery), the lower region of the neck (transverse cervical artery), and the dorsal scapular region (suprascapular artery). The costocervical trunk supplies the deep neck (deep cervical artery) and several intercostal spaces (supreme intercostal artery). The dorsal scapular branch is inconstant; it may arise from the transverse cervical artery. **Clinical: The branches of the subclavian artery anastomose with branches of the axillary artery around the shoulder joint, with branches of the thoracic aorta (intercostal branches) along the rib cage, across the midline of the neck and face via branches from both external carotid arteries, and with the internal carotid arteries and the vertebral branches (circle of Willis on the brainstem). These interconnections are important if the vasculature in 1 region is compromised.

Muscles of mastication - deep

1)Lateral pterygoid ◦sphenoid /lat pterygoid plate to neck of mandible ◦depresses and protracts mandible to open mouth o cranial nerve V3 2) Medial pterygoid ◦lat pterygoid plate/ maxilla/palate to angle of mandible ◦elevates, protracts and lateral movement of mandible for chewing o cranial nerve V3

Lacrimal Gland Innervation diagram

1.Facial nerve (VII) 2.Pterygopalatine ganglion 3.Zygomaticotemporal nerve (V2) 4.Lacrimal nerve (v1)

Branches of the subclavian artery

1.Vertebral artery Ascend through foramen transversarium of cervical spine Form the basilar artery 2.Internal thoracic artery Runs inside thoracic cage Gives off anterior intercostal branches & perforating vessels of breast Additionally, as mentioned earlier, the inferior thyroid artery arises from the first part of the subclavian artery

Venous Drainage of orbit

2 channels Superior ophthalmic vein: Through SOF Into the cavernous sinus Inferior ophthalmic vein either: 1.Joins superior* 2.Passes through SOF on its own* 3.Passes through inferior orbital fissure to join pterygoid plexus

2 extrinsic membranes of larynx

2 extrinsic membranes: a) Thyrohyoid membrane b) Cricotracheal ligament

What are the insertions of the oblique eye muscles?

2 oblique muscles: ◦Inferior and superior *Origin: ◦Inferior: orbital surface of maxilla ◦Superior: body of sphenoid *Insertion: ◦Inferior: post/inferior quadrant ◦Superior: posterior/superior quadrant, via trochlea (bony spur in medial aspect of orbit) *Nerve supply: ◦Inferior (III), superior (IV)

What are the oblique eye muscles?

What are the origins of the oblique eye muscles?

What is the innervation of the oblique eye muscles?

Two blood supply systems to the brain?

2 systems - the anterior and posterior systems: 1) Anterior: Internal carotids 2) Posterior: Vertebro-basilar

How many bones in the skull?

22 (excluding ossicles of ear): 1) mandible (largest bone of skull) 2) (neuro)cranium: a) (vault - houses brain b) base (of skull which brain sits on)) 3) facial skeleton (viscerocranium)

parasympathetic ganglia

3 (ciliary) ,7 (pterygopalatine, submandibular), 9 (otic)

What can two layers of dura mater separate to form? (JAS)

3 layers of meninges: 1) Tough, outer dura mater 2) Delicate, thin, middle layer: arachnoid mater 3) Very thin, inner layer, which closely follows brain surface: pia mater **Dura mater: 2 layers in the brain: a) Outer periosteal layer b) Inner meningeal layer **The 2 layers can separate from each other to form: 1) Dural partitions 2) Intradural venous sinuses

Teeth in deciduous vs permanent set

32 in permament. in deciduous - 20

How many vertebrae are there?

33 (7 cervical, 12 thoracic, 5 lumbar, 5 sacral, 4 coccygeal)

How many vertebrae?

33 (7 cervical, 12 thoracic, 5 lumbar, 5 sacral, 4 coccygeal). vertebral column is very flexible as a whole, but each unit is not. palpable landmarks are spinous processes and not usually found anteriorly

What are the extrinsic eye muscles?

6 in total: 4 recti, 2 obliques. 1) 4 recti muscles: ◦Inferior, superior, medial and lateral *Origin: ◦Common tendinous ring *Insertion: ◦Sclera, 5mm behind corneal margin *Nerve supply: ◦Inferior, superior and medial (III) ◦Lateral (VI) 2) 2 oblique muscles: ◦Inferior and superior *Origin: ◦Inferior: orbital surface of maxilla ◦Superior: body of sphenoid *Insertion: ◦Inferior: post/inferior quadrant ◦Superior: posterior/superior quadrant, via trochlea *Nerve supply: ◦Inferior (III), superior (IV)

What is the structure labelled A? What is the structure labelled B

A - epiglottis; B- nasopharynx; C - oropharynx; D - anterior arch of the atlas (C1 vertebrae). Note that the triangular structure behind is the dens or "peg" of C2 vertebrae; E - laryngopharynx

Petro-tympanic Fissure what passes here?

A branch of cranial nerve VII, the chorda tympani, runs through the fissure to join with the lingual nerve providing special sensory (taste) innervation to the tonguev

How many teeth are present in a complete deciduous set ?

A complete deciduous set has 20 teeth and these usually start to erupt at 6-8 months. Permanent teeth usually start to erupt around six years of age and the usually complete around early twenties (including wisdom teeth.

Cavernous sinus

A sinus containing venous blood located on each side of the body of the sphenoid bone, near the base of the brain, behind the bridge of the nose. bleeds here can damage many cranial nerves travelling through it

Superior sagittal sinus

A venous sinus located in the midline, between the two cerebral hemispheres.

Label this coronal slice through the brain at the level of the hypothalamus.

A) caudate B) internal capsule - splits basal ganglia from thalamus C) putamen D) globus pallidus (ext. and int; medial to putamen) E) amygdala - part of limbic system F) mammillary body G) hippocampus - floor of lateral ventricle H) fornix - beneath corpus callosum, ends up in mammillary body. Y) corpus callosum - interconnects corresponding parts of 2 hemispheres. Z) Thalamus - relay centre for signals to and from cortex. **temporal lobe two structures: amygdala and hippocampus. ** A, C and D form striatum (part of basal ganglia).

Which letter in pic represents the facet for the dens

A. The axis (C2) has a peg like structure called the dens on which the atlas sits. The dens allows the atlas to rotate on the axis and sits in its facet. It is held to the atlas by the transverse ligament of the atlas.

strap muscles

AKA infrahyoid muscles. The move the hyoid and larynx during swallowing movements. Ventral muscles of the neck.

Posterior crico-arytenoid muscle

Abduction and lateral rotation of the arytenoid cartilages

Anterior Cranial Fossa (JAS)

Above the orbits and nasal cavity Contains the frontal lobes

Middle Cranial Fossa (JAS)

Above the pharynx Contains the temporal lobes

Mylohoid muscle

Action - lifts the hyoid bone and larynx during swallowing and opens the mouth, supplied by mandibular branch of trigeminal nerve

laryngeal prominence

Adam's apple (thyroid cartilage)

Vocalis muscle

Adjusts tension of the vocal ligaments

Chorda tympani joining lingual nerve

After entering into the middle ear through the internal acoustic meatus, VII gives off a branch, the chorda tympani... The chorda tympani exits through a different orifice to the main facial nerve, the petrotympanic fissure... •It then enters the infra temporal fossa to join the lingual nerve

The Chorda Tympani (Branch of VII)

Cavernous sinus (JAS)

Against lateral side of body of sphenoid bone Either side of sella turcica Receives blood from the Cerebral veins Ophthalmic veins (orbit) Emissary veins Emissary veins conduct blood from outside the cranium, into the venous sinuses Location on walls leaves structures susceptible to inflammation o Medial border: a) Internal carotid artery b) Abducens nerve (VI) This lies alongside the artery and therefore is susceptible to damage o -Lateral border: a) III b) IV c) V1 d) V2 **The emissary veins can act as a conduit for extracranial infections to reach intracranial areas If emissary veins reach the cavernous sinus, this can lead to complications, especially as multiple nerves and the internal carotid artery run through it.

Hyoid bone

All anterior neck musculature relates to the hyoid No bony articulations; suspended in space by an array of muscles and ligaments.

Facial nerve paths

All facial nerve fibres enter into the petrous part of the temporal bone along with the vestibulocochlear nerve via the INTERNAL ACOUSTIC MEATUS Both the vestibular (VIII) and cochlear (VIII) nerves stay within the middle ear. The facial nerve however, will then divide into its 5 components within the petrous bone.

Innervation to muscles of tongue

All intrinsic and extrinsic muscles of the tongue innervated by the hypoglossal nerve (XII) EXCEPTION: Palatoglossus, innervated by the Vagus (X)

Orbital foramina

All nerves involved in the extrinsic muscles of the eye pass through the superior orbital fossa

Lymph drainage of neck

All of the lymph nodes drain into the deep cervical nodes which lie along the internal jugular vein. These converge to form the right and left jugular lymphatic trunks* Rt jugular lymphatic trunk empties into the rt lymphatic duct* Lt jugular lymphatic trunk enters into the thoracic duct

Why does the lateral part of buccal floor feel bumpy?

Allow the tip of your tongue to slide off the genioglossal ridge to the lower lateral part of the buccal floor. This feels bumpy because of the lobes of the sublingual salivary glands that lie just deep to the mucosa. A projecting mucosal frill marks the multiple openings of the sublingual ducts.

Which nerve innervates the parotid gland?

Although the facial nerve passes beneath the parotid, it is the glossopharangeal that provides secretomotor innervations to it

Thyroid angle

Angle where the thyroid laminae join

What are the 3 borders of the anterior triangle?

Anterior border of sternocleidomastoid Midline Inferior border of mandible **Contents: Mainly muscles Hyoid bone Carotids and Internal Jugular Vein

Where to find the pulse in neck

Anterior border of the sternocleidomastoid Above and lateral to the hyoid bone (Basically any point above C6) Keep the head straight because the sternocleidomastoid muscle protects the carotid sheath when the head is turned.

Scalenes (JAS)

Anterior to posterior: a) Contents of carotid sheath: IJV Carotids Vagus b) SC vein c) Phrenic nerve d) Scalenus Anterior e) Brachial plexus roots and SC artery f) Scalenus Medius

Sensory innervation of pharynx

Anterior wall contains posterior opening of nasal and oral cavities and superior opening of larynx. Sensory innervation: Glossopharyngeal and vagus (IX and X) Via the "pharyngeal plexus"* EXCEPTION: Maxillary (V2) innervates small portion of nasopharynx* **Each subdivision has roughly its own innervation Nasopharynx - V2 Oropharynx - CN IX Laryngopharynx - CN X**

What constitutes the neck region?

Anteriorly: from the lower border of the mandible to the manubrium of sternum Posteriorly: fromthe superior nuchal line on the occipital bone to the intervertebral disc between CVII and T1

Lateral pterygoids

Assists in opening jaw; also assists in lateral and medial excursion of the jaw. innervated by CNV

Name this vertebra

Atlas. The Atlas is the top bone (C1) in the vertebral column. It articulates with the skull which sits on the lateral masses. Importantly it lacks a vertebral body and it is located posterior to the mouth

Mylohyoid muscle (JAS)

Attachments: Body of mandible (mylohyoid line) Body of hyoid **Innervation? V3 **Function? Support floor of oral cavity Elevates the hyoid

Middle and inner ear exist within which bone?

Both the middle and inner ear exist within the petrous part of the temporal bone The middle ear conducts sound from the tympanic membrane to the oval window

mental nerve

Branch of the fifth cranial nerve (trigeminal that splits into inferior alveolar and lingual) that affects the skin of the lower lip and chin.

Laryngeal surface anatomy

By sight and palpation identify the laryngeal prominence (thyroid cartilage) on each other's neck. Explore by gentle palpation the other parts of the thyroid cartilage: the notch in the superior border, and the two laminae. Follow the anterior border of the cartilage downward until you feel a depression due to the cricothyroid membrane and then the convex anterior part of the cricoid cartilage below it. Below the cricoid cartilage (in the interval bounded by the sternomastoids and the jugular notch of the manubrium) can be felt the first two rings of the trachea. The hyoid bone lies above the thyroid cartilage and is connected to it by the thyrohyoid membrane. Gently palpate the body anteriorly, and the horns laterally.

Atypical vertebrae C1

C1 - these are important as allow movement of head and neck. also fractured in road traffic accidents. if broken - death/paralysis. Atlas = C1. Has skull sitting on it. at underside of skull have two facets. missing a vertebral body is not connected to this vertebra, but is attached to the vertebra below - this creates a joint around which these two vertebra can move. if neck udergoes extreme extension or flexion it's possible for the odontoid peg to break free of ligaments and crush the spinal cord/ lower part of medulla coming out of foramen magnum --> death. No spinous process. Foramen transversium - for vertebral arteries

The body of the hyoid bone can be found at which vertebral level?

C3. Note the following vertebral levels of the neck: C1 - open mouth, C2 - superior cervical ganglion, C3 - body of the hyoid, C4 - upper border of the thyroid cartilage and the bifurcation of the common carotid artery, C6 - cricoid cartilage and the middle cervical ganglion and C7 - inferior cervical ganglion.

Which spinal nerve roots contribute to the superior trunk of the brachial plexus?

C5-C6 contribute to the superior trunk, C7 to the medial trunk and C8-T1 to the inferior trunk

Space between dura and spinal cord allows what?

CSF flow, LAs

Cerebrospinal fluid - function (JAS)

CSF is present in the ventricles. A common misconception is that fluid from the brain tissue drains into the CSF This is NOT TRUE. Extracellular fluid drains BACK into capillaries across the blood brain barrier. CSF is very different to extracellular fluid, it has a different composition and function. **Function: 1) Shock impact: Protection of the brain 2) Nutrition of the brain. Whilst the blood provides most of the nutrition, the CSF also helps to maintain nutrient homeostasis.

tragus

Cartilaginous projection anterior to the external opening of the ear

Which branch of the facial nerve innervates the platysma?

Cervical

Tonsils (JAS)

Collections of lymphoid tissue 1) Palatine tonsils (you can see them): Between palatoglossal and palatopharyngeal folds. 2) Tubal Tonsils*: Located posterior to the opening of the nasotympanic tube, lateral wall of nasopharynx 3) Lingual tonsil: Posterior aspect of the tongue. 4) Pharyngeal tonsil (Adenoid Tonsil): Roof of the nasopharynx. Clinical significance: they can become infected/inflamed

posterior longitudinal ligament

Connects all the posterior surfaces of vertebral bodies. runs in vertebral canal

Straight sinus

Connects inferior sagittal sinus to confluence of sinuses. dural sinus that drains blood from the deep center of the brain to collect with the other sinuses

Which structures pass through cavernous sinus in eye?

Cranial nerves III, IV, V(1), V(2), VI, internal carotid and sympathetic carotid plexus all pass through the cavernous sinus or lie within its walls

Bell's palsy (JAS)

Damage to the facial nerve can result in Bell's palsy: There will be ipsilateral facial drooping Here, the right side of his face is affected The patient is trying to show his teeth and raise his eyebrows, but his right facial nerve is damaged

Posterior cranial fossa contains what (JAS)

Deepest and largest fossa Contains the brainstem and cerebellum (above which lie the occipital lobes)

Clinical testing eye muscle

Different to anatomical movements This is because you need to isolate the muscle by eliminating horizontal movement *For example: To isolate the function of the superior oblique bring the axis of the tendon into the axis of the eyeball through adduction (as the superior oblique normally abducts). Then test depression.

Which letter indicates the structure which passes through the foramen magnum of the skull?

E. Vertebral arteries (E) arise from the subclavian artery shortly after the common carotid artery and enter the skull via the foramen magnum. The vagus nerve (D) exits the skull through the jugular foramen. The recurrent laryngeal nerve (indicated by A) is a branch of the vagus nerve. The phrenic nerve (C) originates from C3,4 and 5 and therefore does not pass through the skull. Letter B indicates the scalenus anterior muscle. This question expects integration of knowledge between session 2 (cranium and the brain) and session 3 (root of the neck).

When does vestibulocochlear nerve separate?

Enters the middle ear through the internal acoustic meatus (along with VII) and then splits into the vestibular and cochlear nerves (both SSA). The vestibular nerve has 2 branches: Upper branch, SSA fibres to the semi-circular canals and utricle Lower branch, SSA fibres to the saccule The cochlear nerve runs straight to the cochlea The vestibulocochlear nuclei exist in the pons/medulla

Innervation of cricothyroid muscle

External laryngeal nerve *Forward and downward movement of the thyroid cartilage along the cricothyroid joint *This increases tension on the vocal ligaments--> Increases the pitch

The Tongue - Motor Function

Extrinsic and intrinsic muscles: 1) Extrinsic muscles (HINT: glossus) Palatoglossus Styloglossus Hyoglossus Genioglossus People Say Hello + Goodbye All intrinsic and extrinsic muscles of the tongue innervated by the hypoglossal nerve (XII) EXCEPTION: Palatoglossus, innervated by the Vagus (X) Some argue this is actually a muscle of the palate*

Venous drainage of brain (JAS)

Following gas exchange, the capillaries join to become VENULES like in any other tissue The cerebral veins however DO NOT go straight to the internal jugular vein. - They first drain into the DURAL VENOUS SINUSES Dural venous sinuses are endothelial lined spaces between the outer periosteal and inner meningeal layers of dura mater. They usually exist in the outer regions of the dural folds Blood in the dural venous sinuses will all ultimately drain into the INTERNAL JUGULAR VEIN to return to the heart EXCEPTION*: There is a connection between the cavernous sinus and the pterygoid plexus, the latter of which drains into the maxillary vein.

Describe the ligaments, meninges and spaces traversed by the needle during positioning into the epidural or sub-arachnoid spaces. Discuss clinical uses

For epidural - pass supraspinous ligament, intraspinous and ligamentum flavum. subarachnoid - pass supraspinous ligament, intraspinous and ligamentum flavum, dura and arachnoid mater * epidural - labour * subarachnoid - c-section, spinal block

Transverse slice through neck showing four components

Four components: muscular component, visceral component (thyroid, parathyroid and trachea surrounded by pretracheal fascia) , two vascular components (internal jugular vein, carotid artery and vagus nerve). These four components are bounded by deep fascia in neck which holds it all together (prevertebral, pretracheal, and vascular/carotid sheath)

CSF drainage (JAS)

From the subarachnoid space, the CSF will drain into the dural venous sinuses via Arachnoid villi

Pathways of vagus nerve (JAS extra)

GSA fibres from the larynx via the superior and recurrent laryngeal nerves, and from the epiglottis and valleculae GVA fibres from the aortic body, arch and thoraco-abdominal viscera SVA taste fibres to the epiglottis and valleculae GVE fibres to the mucous glands in the pharynx/larynx and to the thoraco-abdominal viscera SE fibres from the nucleus ambiguus to the pharyngeal and laryngeal muscles

Different fibres of CN IX

GSA fibres travel to the posterior 1/3 tongue, palatine tonsils, oropharynx, middle ear and pharyngotympanic tube GVA travel to the carotid sinus and body SVA travel to the posterior 1/3 tongue GVE fibres travel to the otic ganglion via the petrous bone: From the otic ganglion they hitchhike onto the auricotemporal nerve (V3) to reach the parotid gland

Which muscles does hypoglossus innervate?

GSE fibres from hypoglossal nucleus travels to muscles of the tongue: hyoglossus, genioglossus, styloglossus. **NOT palatoglossus (innervated by vagus)**. Nerves from the C1 root hitchhike onto the hypoglossal nerve just anterior to the internal jugular vein Some of these fibres then immediately descend into the ansa cervicalis. Other fibres supply the thyrohyoid and geniohyoid muscles.

Which ganglion does greater petrosal nerve go to?

Greater petrosal carries GVE and SVA fibres to/past the pterygopalatine ganglion. From there onwards, the fibres join V2 Chorda tympani exits the cranium via the petrotympanic fissure and carries GVE and SVA fibres to the lingual nerve (V3) Extracranial component exits the cranium via the stylomastoid foramen and carries special efferent fibres to the muscles of mastication and posterior strap muscles.

nuchal ligament

Helps to stabilize head and allows shoulders and head to be more independent. Allows improved balance during running. Continuous with supraspinous ligament

What happens if there is impaired sympathetic innervation to eye?

Horner's syndrome - lesion to the upper sympathetic trunk Usually caused by an apex lung tumour (Pancoast's tumour): a) Partial ptosis: only the superior tarsal muscle is affected, not the levator palpebrae superioris) b) Miosis (constricted pupil): As the dilator pupillae is affected c) Anhydrosis (reduced sweating) **Lesion to the entire oculomotor? Complete ptosis**

What major vein does the carotid sheath contain

IJV - The internal jugular vein

What is the clinical significance of the tentorial notch?

If intracranial pressure superior to the cerebellar tentorium is increased, it may force part of the temporal lobe through this notch. This is referred to as a tentorial brain herniation.

Brain herniation (JAS)

Increased pressure in the brain can cause parts of the brain to shift beyond the dural folds into another region causing compression This could be due to any space occupying lesion

Mastoid antrum and middle cranial fossa

Infection can travel down the eustachian tube to the mastoid antrum and air cells and then erode the temporal bone **also: upper teeth are close to the maxillary sinus Infection can travel into the sinus from the roots of the teeth. **sphenoidal sinus provides a route of surgical access, via the nose, to pituitary tumours

Briefly explain the margin and walls of the bony orbit and name its important contents

Inferior to the anterior cranial fossa Anterior to the middle cranial fossa *Pyramid shaped structure containing: a) Eyeball b)Extraocular muscles c) Lacrimal apparatus Bones involved: 1) Roof (1): Orbital plate of frontal Some contribution from sphenoid* 2) Lateral wall (2): Greater Wing of sphenoid. Orbital plate of zygoma. 3) Floor (1): Orbital plate of maxilla. Orbital plate of zygoma*. Little contribution from pyramidal plate of palatine* 4) Medial Wall (4): Frontal process of the maxilla Lacrimal bone. Orbital plate of ethmoid bone. A little contribution from lesser wing of sphenoid. Apex points posteromedially* Base opens on to the face*

CN XII Injury appearance

Injury to the hypoglossal nerve will cause the Tongue to deviate TOWARDS the lesion. In a long standing injury there will also be muscle wasting

Innervation of larynx

Innervated entirely by Vagus (X) - no exceptions: o Superior Laryngeal: Internal - sensation above vocal folds External - one muscle, the cricothyroid o Recurrent Laryngeal :sensation below vocal folds and all other muscles Damage to recurrent laryngeal is associated with hoarseness and deepening voice. Bilateral damage can be life-threatening.

cranial base can be divided into 3 fossae:

It can be divided into 3 fossae: Anterior Middle Posterior

cruciate ligaments attachments

It is an important ligament that holds the posterior dens of C2 in articulation at the atlanto-axial joint. It lies behind a large synovial bursa (surrounded by loose fibrous capsule) and consists of two bands: Longitudinal band: joins the body of the C2 (axis) to the foramen magnum Transverse band: attaches to the inner margin of the C1 (atlas) lateral masses on both sides.

Pterion

Junction of frontal, parietal, greater wing of sphenoid, and temporal bones. The bone is generally thickest in the occipital region and thinnest at the pterion. close relationship between the pterion and the course of the MIDDLE MENINGEAL artery.

pterion

Junction of frontal, parietal, sphenoid, and temporal bones

Corneal Reflex

Just know the afferent and efferent arms Even scientists aren't quite 100% sure about the internal wiring **Afferent: Sensation to touch is conducted via the ophthalmic Nerve (V1) **Efferent: Facial motor nucleus (VII) à along facial nerve to orbicularis oculi (snaps the eye shut) This also has direct and consensual components*

Which of the following vertebrae can be found at the level of the iliac crest: C7/ T3/ T7/ L3/ L4

level of iliac crest

fill in labels of skull superior view (JAS)

LHS (top to bottom): 1) coronal suture 2) parietal bone 3) lambdoid suture 4) occipital bone RHS (top to bottom): 1) frontal bone 2) bregma 3) sagittal suture 4) parietal foramen 5) lambda

Label these foramina in the skull (JAS)

LHS (top to bottom): a) foramen rotundum b) foramen ovale c) carotid canal d) foramen spinosum e) jugular foramen f) foramen magnum RHS (top to bottom): a) cribiform plate b) optic canal c) superior orbital fissure d) foramen lacerum e) internal acoustic meatus f) hypoglossal canal

label this lateral section of nose

LHS (top to bottom): o frontal process of maxilla o lacrimal bone o superior concha, middle conchae, uncinate process of ethmoid o middle pterygoid plate of sphenoid bone o perpendicular plate of palatine bone o inferior conchae *RHS (top to bottom): o nasal bone o lateral process of septal cartilage, major alar cartilage, minor alar cartilage

Lacrimation

Lacrimal gland secretes tears They are washed inferomedially on blinking* Drain via the lacrimal canaliculi* into the lacrimal sac Through the nasolacrimal duct Into the anterior part* of the inferior meatus

Lacrimal system

Lacrimal gland: ◦ is in the anterolateral superior orbit, under LPS muscle ◦parasympathetic secretomotor fibres (CNVII) from pterygopalatine ganglion via zygomaticotemporal and finally lacrimal nerves o lacrimal sac - medial canthus of eye o Nasolacrimal duct - drains into inferior meatus of nose - lacrimal gland tears wash over cornea : protective and keeps eye moist, and tears collect in lacrimal sac and drain into nasolacrimal duct into nose. if dry eye; wonder if there is parasympathetic issue

Which muscle/s of mastication depresses and protracts the mandible in order to open the mouth?

Lateral Pterygoid. All the muscles of mastication have motor innervation from the mandibular branch of the trigeminal nerve. The massester elevates the mandible, temporalis elevates and retracts the mandible, the lateral pterygoids depress and protract the mandible and the medial pterygoids elevates, protracts and enables lateral movement of the mandible. Orbicularis oris keeps a seal around the mouth but isn't actually a muscle of mastication. The orbicularis oris is innervated by the facial nerve.

Oculomotor Nerve Route

Leaves brain from the interpeduncular fossa* Passes along the lateral wall of: Cavernous sinus Before entering the orbit it divides into superior and inferior divisions The parasympathetic component of III travels down the inferior division only Both enter the orbit through? Common tendinous ring in the superior orbital fissure

map of nuclei in brain

Let's quickly recap nerve fibres: Visceral: Innervates an internal organ Somatic: Involves general sensation, eye and ear innervation, tongue muscles General: Relates to touch sensation Special: Relating to the senses (except touch) and the muscles of expression and mastication

What is the innervation to the the muscle of the upper eyelid?

Levator palpebrae superioris: Muscle of upper eyelid *Origin: ◦Lesser wing of sphenoid *Insertion: ◦ Superior tarsal plate and skin of eyelid *Nerve supply: ◦III + sympathetic to smooth muscle (assessment of sympathetic nerve supply: symptom of Horner's syndrome (droopy eyelid)

What is the insertion of the muscle of the upper eyelid?

What is the muscle of the upper eyelid?

What is the origin of muscle of the upper eyelid?

Phrenic Nerve relation to the scalenus anterior?

Lies Anteriorly to scalenus anterior **Originates from anterior rami of: C3,4,5 (keeps the diaphragm alive) **Motor to diaphragm and sensory to peritoneum and pleura around diaphragm **In posterior triangle **Lies Anteriorly to scalenus anterior **Enters thorax between subclavian artery and vein

Swallowing process

Lift and retract tongue (styloglossus, intrinsic muscles) Bolus into oropharynx (palatoglossus) Close off nasopharynx by raising soft palate Raise the larynx, closed off by epiglottis Peristaltic wave of constrictor muscles (superior, middle and inferior) Relax cricopharyngeus, open oesophagus

If there is a lesion to the oculomotor nerve, what will happen? (3 marks)

Loss of movement of ocular muscles except LR and SO. 1.Eye in 'down and out' position Loss of innervation to the levator palpabrae superioris 2.Complete ptosis Loss of parasympathetic function 3.Dilated pupil (mydriasis) The sympathetic nerves travel to the dilator pupillae by hitchhiking onto (what nerve?) and therefore are not affected in an oculomotor palsy

What are the three parts of ethmoid bone

Made up of 3 parts: Cribriform plate Perpendicular plate Ethmoidal labyrinth ** extra point on JAS**

Edinger-Westphal nucleus

Midbrain nucleus of oculomotor nerve containing the autonomic parasympathetic neurons that constitute the efferent limb of the pupillary light reflex and lens control.

Tongue muscles and innervation

Muscles: ◦styloglossus (retract tongue) ◦hyoglossus (to hyoid bone) ◦genioglossus ( tongue to mandible; if issue here in hypoglossal nerve there is deviation TOWARDS the lesion; contrast to uvula which is away from lesion) ◦intrinsic muscles CN XII (hypoglossal nerve - under tongue) - lingual nerve (mixed cranial nerve components) - supplies tongue with touch sensation and taste perception

The pharynx (JAS)

Musculo-fascial passage which facilitates both food and air Connects nasal and oral cavities with larynx and oesophagus. Superior limit: Base of skull Inferior limit: CVI

Where does pharynx start?

Musculo-fascial passage which facilitates both food and air Connects nasal and oral cavities with larynx and oesophagus. Superior limit: Base of skull Inferior limit: CVI

where does pharynx end?

Musculo-fascial passage which facilitates both food and air Connects nasal and oral cavities with larynx and oesophagus. Superior limit: Base of skull Inferior limit: CVI

What is contained within pharynx?

Nasopharynx Oropharynx Laryngopharynx Superior, middle and inferior constrictors: how food is pushed down into upper GIT, sequential contraction of these pushes food bolus down into GIT. very sensitive ◦Sensory: IX, X (pharyngeal plexus - sensory plexus for pharynz) ◦Motor: X, (XI) ◦Aid swallowing

Epiglottis (JAS)

Note its attachment to the thyroid via the flexible thyroepiglottic ligament* (additional info) Retroflexes over the pharyngeal isthmus to protect it during swallowing

Space between dura and bone in brain vs vertebral canal

Note that, unlike in the cranial cavity, where the dura is closely adherent to the inner table of the skull, there is space between the dura and the bone of the vertebral canal

difference in feelinge between hard and soft palate?

Note the ridged mucosa of the hard palate, through which the bony palate (maxilla and palatine bones) is easily felt. Behind this feel the smooth surface of the soft palate; the tip of the tongue can push this upwards towards the roof of the nasopharynx.

Maxillary sinus close to upper teeth --> implication?

Notice how close the upper teeth are to the maxillary sinus Infection can travel into the sinus from the roots of the teeth **sphenoidal sinus provides a route of surgical access, via the nose, to pituitary tumours ** mastoid air cells and middle cranial fossa: Infection can travel down the eustachian tube to the mastoid antrum and air cells and then erode the temporal bone

How to test motor component of facial nerve?

On your partner, test the motor component of the facial nerve. Specifically ask them to look up at the ceiling (look for creasing of the forehead as frontalis contracts), keep eyes closed against resistance (orbicularis oculis) and bare their teeth (risorius). Bell's palsy can affect ability of these functions

Where to test function for V1, v2 and v2

On your partner, using the cotton wool pads provided, test the sensory divisions of the trigeminal nerve. Ask them to close their eyes and then gently touch the skin in each of the dermatomes bilaterally (test in a random order), asking them to report when they feel the cotton wool. Test the motor function of the mandibular division of the trigeminal nerve by palpating masseter as your partner clenches their teeth.

Facial Innervation of Tongue and Salivary Glands:

Once the VII fibres of the chorda tympani have reached the lingual nerve (V3) they will journey to the submandibular ganglion Salivary glands: o The parasympathetic motor fibres (GVE*) synapse in the ganglion and innervate the submandibular and sublingual glands Tongue: o The taste fibres (SVA*) bypass the ganglion and travel to the anterior 2/3 tongue

Nerve supply to sinuses

Ophthalmic (V1): Frontal, sphenoid + ethmoid sinuses Maxillary (V2): Maxillary sinus

Nerve pathways to eye

Ophthalmic branch of the trigeminal (V1) This nerve is only sensory However both parasympathetic and sympathetic nerve fibres hitchhike here Oculomotor (III) Motor fibres to MR, SR, IR, IO &LPS It also has a parasympathetic motor component to the sphincter pupillae and ciliary body Sympathetic nerves (T1) These hitchhike onto the oculomotor nerve to reach the superior tarsal muscle and onto V1 to reach the dilator pupillae and blood vessels of the eye. Trochlear nerve (IV) - SO Abducens nerve (VI) - LR

Lymph nodes in neck

Organised in a ring Each group drains area above it Some are arranged vertically These are named after the jugular veins Everything drains superficial to deep

Salivary glands 3 pairs in buccal cavity

Parotid (mainly serous): IX (glossopharyngeal) ◦passes through parotid duct into mouth and opening upper second molar, parotid duct pierces cheek through buccinator muscle. parotid gland is also a landmark for emergence of branches of facial nerve BUT it is not innervated by facial nerve Submandibular (mainly serous): VII (facial) Sublingual (mainly mucous): VII (facial) - supplied by parasympathetic nerves

Respiratory epithelium functions

Pathways in the head and neck which mediate the passage of air to the lower respiratory tract Lined with respiratory epithelium, which has two functions: 1.Removes trapped particles 2.Warms and humidifies air

Through which vein does central venous access occur

Placed either into neck (internal jugular) Thorax (subclavian) Groin (femoral) - higher risk of infection Right internal jugular is preferred as it is larger and straighter than left, why?

Clinical use of sphenoidal sinus?

Provide a route of surgical access, via the nose, to pituitary tumours **also: upper teeth are close to the maxillary sinus Infection can travel into the sinus from the roots of the teeth. ** mastoid air cells and middle cranial fossa: Infection can travel down the eustachian tube to the mastoid antrum and air cells and then erode the temporal bone

Where do internal carotid artery and oculomotor nerve meet?

Recall that the internal carotid artery and oculomotor nerve meet in the cavernous sinus

Brachial plexus

Responsible for innervating the upper limb Formed from anterior rami of C5-C8 and T1 Trunks pass between Scalenus Anterior and Scalenus Medius and proceed into the upper limb via the axilla

What is brachial plexus formed from?

Responsible for innervating the upper limb Formed from anterior rami of C5-C8 and T1 Trunks pass between Scalenus Anterior and Scalenus Medius and proceed into the upper limb via the axilla

Course of the Carotids

Right common carotid is a branch of the brachiocephalic trunk Left common carotid comes directly from aortic arch. Both enter neck POSTERIOR to the sternoclavicular joints Ascend in CAROTID SHEATHS BIFURCATE at the level of C4: External - supplies many arteries in the face and neck Internal - ascends into cranium before dividing

Function of larynx

Routes air and food into the proper channels (keeps food out of airway), and plays a role in speech

How can feel papilla of parotid duct?

Run your tongue round the insides of the cheeks. These are smooth except for a small, raised and roughened patch near the second upper molar tooth. This is the papilla of the parotid duct

Which movement is best used to test the spinal accessory nerve?

Shrugging the shoulders. o This is testing the power in the trapezius muscle, a muscle innervated by the spinal root of the accessory nerve. Another muscle innervated by cranial nerve XI is the sternocleidomastoid, which can be tested by turning the head so the patient is looking away from the midline and then asking them to turn it back to the centre against resistance. Answer 4 is incorrect and impractical. Answer 5 is testing the muscles of mastication, (in particular the masseter) which are innervated by mandibular branch of the trigeminal nerve

Superficial fascia of neck

Skin Subcutaneous Fat Platysma: Innervated by cervical branch of CN VII

Drainage from meati in nose

Sphenoethmoidal recess (blue) Superior meatus (red) Middle meatus (green) Inferior meatus (purple) Ophthalmic (V1): Frontal, sphenoid + ethmoid sinuses Maxillary (V2): Maxillary sinus

Thyro-arytenoid and Oblique arytenoid muscles (JAS extra)

Sphincter of laryngeal inlet Narrows the laryngeal inlet by pulling the arytenoid cartilages forward while simultaneously pulling the epiglottis toward the arytenoid cartilages Contraction occurs as part of pharyngeal phase of swallowing

Two parts of frontal division of ophthalmic nerve (v1)

Splits into 3 branches 1.Frontal: Supra-orbital Supratrochlear 2.Lacrimal 3.Nasociliary Many branches *GSA fibres from the upper parts of the face, conjunctivae, cornea and ethmoidal sinuses via all the branches * Hitchhiker nerves a)Parasympathetic GVE fibres from the facial nerve (VII) hitchhike on V2 (zygomatic) and then the lacrimal branch of V1 From here they travel to the lacrimal gland. b) Parasympathetic GVE fibres from the oculomotor nerve (III) travel to the ciliary ganglion and then hitchhike on the short ciliary nerve to the sphincter pupillae and ciliary body c) (blue box)Sympathetic fibres (T1) from the superior cervical ganglion travel to the carotid plexus and then hitchhike onto the ciliary nerves à dilator pupillae and the blood vessels of the eye

What is structure B?

Structure A = Uvula, B = Palatopharyngeal fold, C = Palatine tonsil, D = Palatoglossal fold and E = Posterior wall of the oropharynx. Note that during inspection of the oral cavity one can look for inflammation of the palatine tonsils (lymphoid tissue). Other tonsils include the pharyngeal tonsils and the lingual tonsils (under the tongue). The position of the uvula is also important to asses. This can be done by asking the patient to say "ah". If the Uvula deviates to one side there may be a palsy of the vagus nerve.

Subclavian Artery and Brachial Plexus

Subclavian artery becomes the axillary artery at the lateral margin of the 1st rib The cords of the brachial plexus are named due to the relation to axillary artery

Lymphatic drainage of neck

Superficial Anterior and Lateral Lymph Nodes lie along the External Jugular Vein in the superficial fascia --> drain into the *Deep Cervical Lymph Nodes*, which lie deep to the SCM, along the Internal Jugular Vein - Superior deep/jugulodigastric and Inferior deep/jugulo-omohyoid - Supraclavicular Lymph Nodes - vocal cords have no lymphatic drainage - important to know for cancer (head, neck or chest and abdo) - should know where to palpate - can receive lymph from upper abdomen or chest - can get upper drainage too

Superficial extrinsic muscles on back

Superficial extrinsic muscles including trapezius, latissimus dorsi, levator scapulae and the rhomboids. These muscles are involved in arm, shoulder and back movement

The pulse of which artery can be felt anterior to the ear?

Superficial temporal artery. The temporal pulse of the superficial temporal artery (a branch of the external carotid) can be felt just in front of the ear.

Venous drainage flowchart (JAS)

Superior Petrosal sinus can also drain into transverse sinus. Inferior Petrosal sinus drains into Internal Jugular vein

Orbicularis Oculi innervation

Surrounds eye Innervation?: Facial nerve VII Lesion to VII: Inability to shut eyes tightly - tear spillage and dry eye

When do the anterior and posterior fontanels close? (JAS)

Sutures - fibrous joints that allow little or no movement. Anterior Fontanelle closes between 18-24 months of age Posterior fontanelle closes from the first 2-3 months

Infant skull - superior view

Sutures aren't fully fused and hence get fontanelle's which is piece of soft part of head - helps when baby has to come out of birth canal

Which of the following vertebral levels have the smallest level of flexion/extension movement?C1 and C2/ T1-T6/ L1-S5/ T7-T12/ C5-C7

T1-T6. The thoracic part of the vertebral column (T1-T6) articulates with the ribs and therefore has limited movement. T1-T6 has virtually no flexion or extension and only minor levels of lateral flexion and rotation

A uncal herniation affects which dural fold?

Tentorium cerebelli. When there is raised intracranial pressure above the tentorium cerebelli due to e.g. a mass occupying lesion or a bleed, the medial temporal lobe (uncus) can herniate around the ridge free edge of the tentorium and put pressure on the side of the brain stem. This is known as an uncal or tentorial hernia. It can result in unconsciousness. The falx cerebelli divides the cerebellum into right and left lobes and the falx cerebri does the same for the cortex. Herniation of cortex through the falx cerebri is known as a subfalcine hernia and it is usually of little clinical significance. Herniation of the cerebellar tonsils through the foramen magnum puts pressure upon the medulla and can result in cardiorespiratory failure. The diaphragm sellae covers the hypophysial fossa in the sella turcica. The arachnoid membrane is not part of the dura mater but is the meningeal layer beneath.

Greater petrosal nerve - part of which nerve? path?

The 1st branch - greater petrosal nerve. Upon entering the petrous bone, the SVA taste fibres and GVE parasympathetic fibres will exit the bone back into the cranial fossa via the greater petrosal nerve. The greater petrosal nerve will go onto exiting the cranium via the pterygoid canal where the GVE fibres will eventually synapse at the pterygopalatine ganglion.

Middle Ear three ossicles

The 3 ossicles transmit vibrations from the tympanic membrane to the oval window: 1) Malleus: Tensor tympani muscle (V3): Pulls the handle of the malleus medially. This tenses the tympanic membrane, reducing the force of vibrations in response to loud noises 2) Incus 3) Stapes: Stapedius (VII): Pulls the stapes posteriorly to prevent excessive oscillation **Pharyngotympanic (Eustachian) tube: Equalises barometric pressure between the middle ear and the external environment

Regarding the muscles of the anterior triangle, which of the following statement are true? The platysma is supplied by the mandibular division of the trigeminal nerve/ The anterior belly of the digastric muscle is supplied by the facial nerve/ The anterior belly of the digastric muscle is supplied by mandibular division of the trigeminal nerve/ The mylohyoid is supplied by the facial nerve/ The infrahyoid (strap) muscles are all supplied by the ansa cervicalis

The anterior belly of the digastric muscle is supplied by mandibular division of the trigeminal nerve. o The anterior belly of the digastric muscle is supplied by the mandibular division of the trigeminal nerve and the posterior belly is supplied by the facial nerve. The facial nerve also innervates the platysma whilst the mandibular division of the trigeminal nerve innervates the mylohyoid. Not ALL the strap muscles are supplied by the ansa cervicalis because the thyrohyoid is supplied by C1 fibres via the hypoglossal nerve.

Which of the following defines part of the posterior triangle of the neck? The mandible/ The hyoid bone/ The anterior belly of the digastrics muscle/ The anterior margin of the trapezius muscle /The stylohyoid muscle

The anterior margin of the trapezius muscle. The posterior triangle is defined anteriorly by the posterior margin of the sternocleidomastiod, posterioly by the anterior margin of the trapezius muscle, and inferiorly by the middle third of the clavicle.

Innervation summary of suprahyoid and infrahyoid muscles

The anterior suprahyoid muscles are innervated by V3 The posterior suprahyoid muscles are innervated by the VII The infrahyoid muscles are innervated by the ansa cervicalis **Exceptions: Geniohyoid &Thyrohyoid, are both innervated by C1 fibres via the hypoglossal nerve

Where does chorda tympani exit?

The chorda tympani exits through a different orifice to the main facial nerve, the petrotympanic fissure...

Ciliary branches of the nasociliary nerve (V1)

The ciliary branches of the nasociliary nerve (V1) are important for 2 reasons 1.Oculomotor parasympathetic fibres (III) à the inferior branch of III to the ciliary ganglion. From here, the fibres leave III and hitchhike onto the ciliary branches of V1 to travel to the: Sphincter pupillae and the ciliary body 2.Sympathetic fibres (T1) from the superior cervical ganglion travel to the carotid plexus and then use the ciliary branches of V1 to travel to the: Dilator pupillae and Blood vessels of the eye

What does circle of willis act a connection between?

The circle of Willis acts as a connection between the two systems (anterior and posterior) Anteriorly, the circle is completed by the anterior communicating artery which joins the two anterior cerebral arteries. Posteriorly, each middle cerebral artery is connected to the corresponding posterior cerebral artery via a posterior communicating artery.

Anterior blood supply to brain

The common carotid arteries split into the internal and external carotids at the vertebral level C4 The internal carotid artery enters the cranium through which foramen? = Carotid canal Up until this point the artery has no branches

Meandering course of facial artery implications

The facial artery meanders around the mandible. At some parts it is protected by the ramus of the mandible At others it is superficial and can be easily damaged.

Which nerve supplies the parasympathetic innervation to the submandibular and sublingual salivary glands?

The facial nerve is the main motor nerve supplying the muscles of facial expression and, via the chorda tympani, is the nerve that supplies the parasympathetic innervation to the submandibular and sublingual salivary glands.

When studying an anterior coronal MR image through the frontal lobe, what deep grey matter structures would you be likely to see?

The head of the caudate nucleus, but not the lentiform nuclei nor the thalamic nuclei. Other options describe what you see in planes posterior that referred to in the question, anterior coronal MR image through the frontal lobe.When observing an anterior coronal view through the temporal and frontal lobes you would see both the head and the tail of the caudate, the lentiform nuclei but not the thalamic nuclei.When observing a coronal view through the hypothalamus you would see both the head and the tail of the caudate, the lentiform nuclei and thalamic nuclei.Concerning the last option, you would not see an anterior structure, such as the head of the caudate, in the same coronal plane as the thalamus because the thalamus is posterior to it.

Regarding the carotid pulse, which statement is true? The internal jugular vein is lateral to the carotid pulse/ It can be used to control bradycardia by massaging it/ It cannot be used to assess pulse character/ It is located in the posterior triangle of the neck/ It can also be located on the inferior border of the mandible

The internal jugular vein is lateral to the carotid pulse. The internal jugular vein is lateral to the carotid pulse and this is useful information for central line insertion. Massaging the carotid pulse stimulates the baroreceptors in the carotid sinus, which in turn results in vagal stimulation. This can be used to control supraventricular tachycardias. The carotid pulse can be used to assess pulse rhythm, rate and character and can also be used to time heart murmurs. It is found in the anterior triangle of the neck. The facial pulse is found on the inferior border of the mandible.

Where does the middle thyroid vein drain?

The internal jugular vein. Note both the superior and the middle thyroid veins drain into the internal jugular. Only the inferior thyroid vein drains into the brachiocephalic.

Lacrimal nerve of V1

The lacrimal nerve (V1) is important, as facial nerve parasympathetic fibres (VII) from the pterygopalatine ganglion use the lacrimal nerve to travel to the lacrimal gland (Remember that the fibres first hitchhike onto the zygomaticotemporal branch of V2, and then V1, see the last few slides and come back here)

Functions of larynx

The larynx exists in the lower part of the tract, it has two major functions: 1.Sphincter of the lower respiratory tract 2.Specialized for phonation in humans

Cricoid

The lowest unpaired cartilage What vertebral level? - (C6) ONLY complete cartilaginous ring in all air passages.

Accomodation reflex pathway

The mechanism of accommodation reflex involves three responses: 1) The convergence of both eyes is such that the near object is in focus, which aids in image projection on the fovea. This action involves contraction of the medial rectus muscles of both eyes, with the relaxation of lateral recti resulting in the adduction of both the eyes. 2) Constriction of the sphincter pupillae muscles, pupils constrict, which improves the depth of focus. The divergent rays from distant objects scatter off the periphery of the cornea, and hence they do not fall on the fovea. 3) Contraction of bilateral ciliary muscles results in thickening of the lens, which shortens the focal length, which increases its refractive power (measured in diopters). o The afferent pathway begins with the transmission of the signal from the optic nerve (CNII) to the primary visual cortex. This path involves phototransduction in the retina, thalamic interneurons in the lateral geniculate nucleus, and finally arrival at the visual cortex using optic radiations. o From the visual cortex, the reflex initiates, and impulses get sent to the visual association cortex that in turn has projections to the superior colliculus and pretectal areas. o From here, impulses swiftly relay to the oculomotor and Edinger-Westphal nuclei of cranial nerve III. o The oculomotor nucleus stimulates contraction of the medial recti bilaterally, which results in convergence. o Simultaneously the Edinger-Westphal nucleus coordinates parasympathetic pupillary constriction via the ciliary ganglion. o The same general pathway is responsible for lens thickening, except that instead of arriving at the pupillary sphincter muscles, the short ciliary nerves from the ciliary ganglion terminate at the ciliary muscles and are responsible for muscle contraction. o As the ciliary muscles contract, the suspensory zonules of the lens relax and release the tension of the lens. Thus, somewhat paradoxically, it is the contraction of the ciliary muscles that allows the lens to form a more spherical shape that facilitates accommodation.

Dural folds (JAS)

The meninges surround the brain, and therefore follows the contour of the brain. The dura mater, being the outermost layer forms multiple folds because of this. The image on the right demonstrates the falx cerebri dural fold

The middle meningeal artery arises from which branch of the external carotid?

The middle meningeal arises from the first part of the maxillary artery, which is one of the terminal branches of the external carotid artery. There is no zygomatic branch.

middle meningeal artery arises from? (JAS)

The middle meningeal artery arises from the maxillary artery, which itself is a branch of the external carotid artery This artery supplies most of the dura adherent to the superior cranium

Regarding the blood supply of the thyroid gland, which statement is true? The superior thyroid vein drains into the brachiocephalic vein/ The superior thyroid artery is a branch of the thyrocervical trunk/ The middle thyroid vein drains into the internal jugular vein/ The inferior thyroid vein drains into the internal jugular vein/ The inferior thyroid artery is a branch of the external carotid artery

The middle thyroid vein drains into the internal jugular vein. o The superior and inferior thyroid arteries are branches of the external carotid and the thyrocervical trunk respectively. Both the superior and middle thyroid veins drain into the internal jugular whilst the inferior thyroid vein drains into the brachiocephalic vein.

odontoid peg

The odontoid process (also dens or odontoid peg) is a protuberance (process or projection) of the Axis (second cervical vertebra). It exhibits a slight constriction or neck, where it joins the main body of the vertebra.

What does outer ear consist of?

The outer ear consists of the auricle and the external acoustic meatus (EAM). 1) The EAM collects vibrations and mediates their passage to the middle ear 2) Auricle: A fibrocartilagenous structure with a number of depressions, eminences, and folds: Helix and lobule: Folded outer margin of the auricle Antihelix: Parallel inner margin Tragus and antitragus: Eminences anterior and inferior to the EAM respectively Concha: The auricle's hollow centre

What is the innervation to the pharyngeal muscles?

The pharynx contains circular and longitudinal muscles Motor innervation to muscles: Vagus (X) EXCEPTION: Glossopharyngeal (IX) innervates stylopharyngeus

What nerve innervates the stylopharyngeus muscle?

The pharynx contains circular and longitudinal muscles Motor innervation to muscles: Vagus (X) EXCEPTION: Glossopharyngeal (IX) innervates stylopharyngeus

Clinical significance of sphenoidal sinus and pituitary gland?

The pituitary gland lies in the hypophyseal fossa, a depression seen just superior to the sphenoidal sinus in the sphenoid bone. A tumor of the pituitary gland can be approached surgically through the nasal cavity by passing through the sphenoidal sinus and directly entering the hypophyseal fossa.

The posterior third of the tongue is innervated by which of the following cranial nerves to enable taste sensation?

The posterior two thirds are innervated by the glossopharangeal nerve and at the very back there is some vagal innervations also. Although the hypoglossal innervates the intrinsic muscles of the tongue, it is a motor supply and therefore is not involved in taste sensation. The anterior two thirds of the tongue has sensory innervations from the trigeminal nerve (pain) and the facial nerve (taste).

Pathway of The Sympathetic Fibres to eye

The preganglionic sympathetic fibres originate at T1 Therefore the sympathetic fibres are not part of III or V1, they simply hitchhike They synapse at the superior cervical ganglion. Which level? =C2 The postganglionic fibres travel to the carotid plexus and ophthalmic artery From the carotid plexus they travel to the: Superior tarsal muscle (via superior branch of the oculomotor nerve*) Dilator pupillae (via the ciliary nerves of V1) Blood vessels of the eye (via the ciliary nerves of V1)

Identify the pterion and explain the clinical importance of its relationship to the middle meningeal artery (JAS)

The pterion is the region where the following four bones join together: Greater wing of the sphenoid Frontal bone Parietal bone Temporal bone It is the weakest part of the skull Trauma to the pterion may rupture the middle meningeal artery causing an extradural haematoma

Quadrangular membrane (JAS - extra)

The quadrangular membrane is the other intrinsic ligament It is superiorly connected to epiglottis and inferiorly to the thyroid and arytenoids Is thickened at the bottom to form the vestibular ligament

Innervation of recti muscles

The recti supplied by III are involved in adduction

The three main herniations (JAS)

The three main herniations you need to know are as follows: 1.Subfalcine herniation: o Frontal lobe herniates under the falx cerebri o This is NOT clinically significant 2. Uncal herniation: o The uncus of the temporal lobe herniates below the tentorium cerebelli and compresses the midbrain. o This can lead to LOSS OF CONSCIOUSNESS. 3. Tonsillar herniation: o The cerebellar tonsils move downward through the foramen magnum possibly causing compression of the MEDULLA. o This can lead to CARDIORESPIRATORY ARREST.

Which strap muscle is innervated by the C1 fibres via the hypoglossal nerve?

The thyrohyoid. The infrahyoid or "strap" muscles are all innervated by the ansa cervicalis except for the thyrohyoid which is innervated by the C1 fibres via the hypoglossal nerve. Some also consider the stylopharyngeus to be a strap muscle too, but it is innervated by the glossopharangeal nerve (cranial nerve IX).

The Thyroid Gland is supplied by which arteries?

The thyroid gland is supplied by 2 pairs of arteries: a) Superior thyroid artery: First branch of the external carotid b) Inferior thyroid artery: Arises from the first part of the subclavian artery This artery does not only supply the thyroid, but also supplies the superior oesophagus and the trachea. ** It is drained by pairs of superior, middle and inferior thyroid veins Superior and middle thyroid veins: Drain into the internal jugular vein* Inferior thyroid vein: Drains into brachiocephalic trunk*

The Trigeminal Nerve (CN V)

The trigeminal nerve has three branches. V1 and V2 are sensory (only) The branches of V1 are covered in session 3.2 You do not need to know the branches of V2 V3 has sensory AND motor components The motor component is special efferent* Has 3 main branches: Long Buccal Lingual Inferior Alveolar

Alar ligament attachments

The two superolateral surfaces of the dens possess circular impressions that serve as attachment sites for strong alar ligaments , one on each side, which connect the dens to the medial surfaces of the occipital condyles . These alar ligaments check excessive rotation of the head and atlas relative to the axis.

In the cough reflex, branches of which nerve detect irritation to the larynx and trachea?

The vagus nerve senses irritation, which causes the phrenic nerves and the thoracic nerves to initiate deep inhalation prior to the cough (forced exhalation). Trigeminal branches V1 (ophthalmic) and V2 (maxillary) detect irritation in the nasal mucosa are involved in the sneeze reflex

What are the two actions of the TMJ?

There are 2 actions of the temporomandibular joint: 1)Hinge: elevation and depression of mandible 2) Glide: protraction and retraction of mandible

Deep Muscles of the Anterior Triangle (JAS)

There are 2 main muscle groups: 1) Suprahyoid (x4): Mylohyoid, Stylohyoid, Geniohyoid and Digastric 2) Infrahyoid (x4) AKA Strap Muscles: Sternohyoid, Omohyoid, Sternothyroid and Thyrohyoid Knowing the innervation of these muscles is very important!

Muscles of mastication (JAS)

There are two types of muscle: 1) SUPERFICIAL a) Masseter: Involved in elevation b) Temporalis: Involved in elevation and retraction 2) DEEP a) Lateral pterygoid: Involved in depression and protraction (protrusion) b) Medial pterygoids: Involved in elevation and protraction and lateral movement of the mandible ***To keep it simple, all the muscles elevate the mandible Except for the lateral pterygoids, and their main function is protraction The temporalis is involved in retraction The deep muscles (pterygoids) are involved in protraction***

Regarding the blood supply to the spinal cord, which of the following is the most accurate description? There are two posterior and two anterior spinal arteries/ There is an external vertebral venous plexus but no internal plexus /There is one posterior and two anterior spinal arteries/ There is one anterior artery and two posterior spinal arteries/ The spinal cord only has radicular arteries and an internal plexus

There is one anterior artery and two posterior spinal arteries. The spinal cord has 3 longitudinal arteries consisting of one anterior and two posterior spinal arteries, supplemented by radicular arteries. The spinal cord has a valveless internal and external venous plexus. This extensive blood supply could provide a route for the spread of metastasis to central nervous system.

Facial nerve (VII) motor branches

These are the branches you must know about VII. To reach the muscles of facial expression the facial nerve divides into 5 SE (somatic efferent) branches in the parotid plexus To Zanzibar By Motor Car: - Temporal branches Zygomatic branches Buccal branches Mandibular branch Cervical branch **This parotid plexus is in the parotid gland, but the facial nerve does not innervate this gland You can test this motor component by asking the patient to do a series of facial expressions...

Ophthalmic branch of trigeminal nerve

This nerve is only sensory. However both parasympathetic and sympathetic nerve fibres hitchhike here

Innervation of infrahyoid muscles

Thyrohyoid C1 fibres via the Hypoglossal Nerve (XII) Omohyoid, sternohyoid and sternothyroid Ansa cervicalis (anterior rami of C1 to C3)

hyoid bone

U-shaped bone at the base of the tongue that supports the tongue and its muscles.

Larynx position in relation to hyoid bone and trachea

Under the hyoid bone, above the Trachea **Innervated ENTIRELY by Vagus (X) - no exceptions o Superior Laryngeal: Internal - sensation above vocal folds External - one muscle, the cricothyroid o Recurrent Laryngeal :sensation below vocal folds and all other muscles Damage to recurrent laryngeal is associated with hoarseness and deepening voice. Bilateral damage can be life-threatening.

Trigeminal nerve - Sensory component: Dermatomes of the trigeminal nerve

V1 supplies the forehead skin and upper eyelids via the frontal nerve: o The conjunctiva, sclera, corneal epithelium and inner eyelids via the lacrimal nerve o The nasal mucosa and frontal sinus via the nasociliary. V2 supplies the skin of the anterior temple, the middle of the lateral aspect of the face and the upper jaw (teeth, gums lip etc) V3 supplies the middle part of the temple, cheeks, floor of mouth by buccal nerve: o Lower teeth, gums and lip by inferior alveolar o Anterior two thirds of tongue by lingual

what signals does V2 carry?

V2 is purely sensory GSA fibres from the trigeminal nucleus travel to the middle face, maxillary sinus, teeth, palate, tongue, tonsils and nasopharynx . Parasympathetic fibres from the greater petrosal nerve (VII) hitchhike onto V2: GVE parasympathetic fibres synapse at the pterygopalatine ganglion. Some fibres travel to the lacrimal gland. They first travel via the zygomatic (V2) nerve and then will join the lacrimal (V1) nerve The rest travel to the mucous membranes of the nasal cavity & sinuses travel via infraorbital, pharyngeal and the 3 palatine nerves SVA fibres travel to the soft palate via the palatine nerves where they receive taste information.

Trigeminal Nerve - Motor Component (V3)

V3 supplies the 4 main muscles of mastication Innervation to the masseter, temporalis and pterygoids is mostly by the anterior division of the V3 (before formation of the (purely sensory) long buccal nerve)* Innervation to the anterior suprahyoid muscles (mylohyoid and ant. digastric) is through the mylohyoid nerve which is a branch of the inferior alveolar nerve You can test the motor function of this nerve by asking the patient to clench their jaw (temporalis and masseter), open their mouth (lateral pterygoids) and move it side to side (medial pterygoids)

Mandibular nerve labeled pic

V3 technically breaks into an anterior and posterior division* The anterior division of V3 is the long buccal nerve Not to be confused with the buccal branch of the facial nerve The posterior division splits into the inferior alveolar and lingual nerve **Pic: 1) posterior division 2) anterior division 3) buccal nerve and buccinator nerve (cut) 4) submandibular ganglion 5) mental nerve 6) inferior alveolar nerve (cut) 7) submandibular gland 8) nerve to mylohyoid 9) inferior alveolar nerve (cut) 10) lingual nerve 11) chorda tympani nerve

V3 Branches

V3: Mandibular Long Buccal Lingual Inferior Alveolar: Nerve to Mylohyoid

Intervertebral disc between C1 and C2?

Vertebra C1 (the atlas) articulates with the head. Its major distinguishing feature is that it lacks a vertebral body or a spinous process . In fact, the vertebral body of C1 fuses onto the body of C2 during development to become the dens of C2. As a result, there is no intervertebral disc between C1 and C2. When viewed from above, the atlas is ring shaped and composed of two lateral masses interconnected by an anterior arch and a posterior arch. Each lateral mass articulates above with an occipital condyle of the skull and below with the superior articular process of vertebra C2 (the axis) . The superior articular surfaces are bean shaped and concave, whereas the inferior articular surfaces are almost circular and flat. The atlanto-occipital joint allows the head to nod up and down on the vertebral column. The posterior surface of the anterior arch has an articular facet for the dens, which projects superiorly from the vertebral body of the axis. The dens is held in position by a strong transverse ligament of atlas posterior to it and spanning the distance between the oval attachment facets on the medial surfaces of the lateral masses of the atlas.

branches of vertebral artery

Branches of the basilar artery

Vertebral arteries - come off the 1st part of the subclavian arteries Ascend in the neck; passing through the foramina trasversarium of C1-C6 vertebrae. ooBranches of the Vertebral: a) Anterior spinal (1) - supplies anterior 2/3rds of the spinal cord b) Posterior spinal (2) - supplies posterior 1/3rd of cord c) Posterior Inferior Cerebellar Artery (PICA)* - supplies the posterior inferior aspect of cerebellum Unite to form the basilar artery on the anterior aspect of the pons - Branches of the basilar artery (in order, you don't need to know them all) a) Anterior inferior cerebellar arteries* b) Pontine arteries - several small branches c) Labyrinthine arteries* - long-distance arteries, destined for the ear d) Superior cerebellar arteries* e) Terminal branches at the upper border of pons - posterior cerebral arteries

Vertebro-basilar system (posterior blood supply to brain) (JAS)

Temporo-Mandibular Joint (TMJ)

Very important for mastication. Formed between the head of the mandible which inserts into a socket formed by the articular tubercle and mandibular fossa The 4 muscles of mastication all act to produce movement at this joint

Arterial supply of orbit

Via the ophthalmic artery Branch of the internal carotid artery This artery has 6 branches, which Gentleman has told you. But don't fret about remembering them all: Supratrochlear Muscular branches Ciliary Supraorbital Lacrimal Central artery of the retina Some Men Cut Soldiers Like Cheese

visceral vs somatic

Ways to remember the nerve fibre names Visceral: Innervates an internal organ Somatic: Involves general sensation, eye and ear innervation, tongue muscles Special: Relating to the special senses (excluding touch) and the muscles of expression and mastication

Grand summary of nerve pathways for eye (JAS)

When reviewing these slides, just ensure that you understand: The main branches of V1 The 2 components of the oculomotor nerve Specifically, how the parasympathetic component reaches the sphincter pupillae and ciliary body via the ciliary ganglion and ciliary nerves (V1) That sympathetic fibres (T1) innervate the superior tarsal muscle That sympathetic fibres (T1) innervate the dilator pupillae and blood vessels of the eye by travelling along the ciliary nerves (V1)

What are the faucial pillars?

With the tongue forward and well depressed, inspect the ring-like entrance to the oropharynx. This is bounded above by the soft palate (with the uvula dangling from the middle of its posterior border), below by the posterior part of the tongue, and laterally by a pair of curved ridges running down from the soft palate. These are the faucial pillars. The anterior pair (palatoglossal folds) are produced by the palatoglossus muscles, and the posterior pair (palatopharyngeal folds) by the palatopharyngeal muscles. The muscles themselves are fairly trivial, being a small part of the pharyngeal constrictor system. Their main practical importance is that between the palatoglossal and palatopharyngeal folds on each side is found a (palatine) tonsil.

middle cerebral and anterior cerebral artery from ICA

How to test v3 in the four muscles of mastication

You can test the motor function of this nerve (v3) by asking the patient to clench their jaw (temporalis and masseter), open their mouth (lateral pterygoids) and move it side to side (medial pterygoids)

Testing facial nerve

You can test this motor component by asking the patient to do a series of facial expressions

hyoid bone postion

a U-shaped bone in the neck that supports the tongue.

Tentorial notch

a narrow opening in the tentorium cerebelli that the midbrain passes through

a) What innervates the structure labelled A? b) Branches of which arteries supply structure H c) Name the muscle lettered G d) Which answer describes contents of C? e) Which answer best describes E?

a) A is the trapezius muscle, which is innervated by the spinal accessory nerve. b) Structure H is the thyroid gland. The thyroid is supplied by the superior thyroid (branch of the external carotid) and the inferior thyroid (a branch of the thyrocervical trunk) c) sternocleidomastoid d) Nuchal muscle. C is prevertebral fascia which surrounds vertebral muscles. e) E is a member of the infrahyoid (strap) muscles.

Insertion sites for central venous cannulation

a) internal jugular vein b) subclavian vein c) (femoral vein) - higher risk of infection Right internal jugular is preferred as it is larger and straighter than left

contraction of lateral rectus does what?

abduct pupil away from midline. *n.b. - this is isolated and not acc in real life.

lordosis

abnormal anterior curvature of the lumbar spine (sway-back condition)

Papilla of mouth

across the lower gums and mandibular symphysis to the floor of the mouth - there is a fleshy tag with a forked tip. This is the papilla on which the submandibular salivary ducts open. Suck gently and see if you can feel saliva squirting from these ducts.

contraction of medial rectus does what?

adduct pupil towards midline *n.b. - this is isolated and not acc in real life.

Transverse arytenoid

adducts arytenoid cartilage

Lateral crico-arytenoid

adducts vocal ligaments

paranasal sinuses

air cavities within the cranial bones that open into the nasal cavities. line anterior aspect and facial skeleton. - function: reduce weight of skull, provide crumple zone to protect brain, help with resonation of voice - all supplied by branches of trigeminal nerve - sinusitis very painfus

venous and lymphatic drainage from the face

all drains into internal jugular vein.

pharyngeal tonsil

also called adenoids; located in posterior wall of nasopharynx

nerve supply to digastric muscles

anterior - mandibular branch of trigeminal nerve. posterior - facial nerve

Triangles of neck

anterior and posterior triangles: - sternocleidomastoid muscle that turns head to look over shoulder on opposite site e.g. right muscle turns head left (divides neck into anterior and posterior triangles - between sternum and clavicle up to mastoid process at back of skull behind the ear - digastric muscles (two bellies- anterior and posterior) - involved in movement of hyoid bone - omo hyoid muscle - between hyoid and scapula - trapezius muscle - large triangle muscle that forms neck and allows elevation of scapulae (shoulders)

digastric bellies

anterior belly and posterior belly open mouth. on either side of mylohyoid muscle, also form part of floor of mouth. anterior innervated by mandibular division of trigeminal. posterior belly innervated by facial nerve.

Which of the following ligaments is likely to be damaged in a "whiplash" injury? anterior longitudinal ligament/ posterior longitudinal ligament /ligamentum flava /supraspinous ligament /interspinous ligament

anterior longitudinal ligament. The anterior longitudinal ligament covers and connects the anterior aspect of the vertebral bodies and would be damaged when the neck is hyper-extended during whiplash. This injury occurs frequently at the level of C4/C5 and leads to neck pain, stiffness and headache. Recovery involves supporting the head and neck with a cervical collar that is higher at the back than the front thus putting the cervical vertebrae in a flexed position.

where is anterior longitudinal ligament? why is it important clinically?

anterior to vertebral body. most often involved in whiplash

rhomboid muscle

any of several muscles of the upper back that help move the shoulder blade

what does lumbar enlargement correspond with?

area of spinal cord receiving sensory information and sending motor info to lower limb. contrastingly to cervical enlargement where nerves exit horizontally, here the nerves run down the spinal cord before exiting further down - this is because disparity between length of spinal cord (ends at L2 at conus medullaris; from this the filum terminale runs down to tether spinal cord to sacrum) and length of vertebral canal. fibres at end are called cauda equina. * clinical use of this disparity: lumbar puncture between L3/4 as know spinal cord ends at L2 and can collect CSF

what does cervical enlargement correspond with?

area of spinal cord receiving sensory information and sending motor info to upper limb. can see nerve leaving in pic

condylar process of mandible

articulates with temporal bone

atlanto-axial joint

articulation between the atlas and axis. no joint.

denticulate ligament

band of pia mater that anchors dura mater to cord

extradural space in spine

between dura and bony wall of vertebral canal. used for epidural anaesthetic. in skull no extradural space.

Sagittal suture

between parietal bones

lambdoid suture

between parietal bones and occipital bone

The ligamentum flava is located where

between vertebral arches. Superfically to deep, the supraspinous (3) and interspinous (1) ligaments and ligamentum flava (5) are found respectively. The anterior (4) and posterior (2) longitudinal ligaments run up either side of the vertebral bodies. Together they all work to stabilise the vertebral column.

thyrocervical trunk

blood supply to scapular muscles and thyroid gland

ethmoid

bone that forms the back of the nose and encloses numerous air cells

corneal reflex

both eyes blinking in response to corneal stimulation in one eye by a cotton wisp. o Afferent- V1 (opthalmic- nasociliary branch, levator palpebrae). o Efferent- VII (Temporal Branch, Orbicularis Oculi)

Middle meningeal artery comes off which artery?

branches off the maxillary artery, which is an extension of the external carotid artery

Skull - superior view

bregma is where coronal suture with sagittal suture. lamba is where sagittal suture and lambdoid suture meet

What vessel is lacerated in an subdural hematoma?

bridging veins

Why is it so important to avoid infection of lacerations to the scalp?

bridging veins are there, the infection could get into the bloodstream and become fatal

Olive (Brainstem)

bulge on side of brainstem

sphenoid bone shape

butterfly-shaped bone at the base of the skull

Which is the only cervical vertebra with a prominent spinous process?

what can see when retract tentorium cerebelli

can see contents of posterior cranium fossa (cerebellum and brainstem - lighter mickey mouse shape thing inside). if remove this, get the foramen magnum which is where spinal cord connects to brainstem at base of skull

The superior ophthalmic vein is a route by which a localised facial infection can spread to become a life-threatening illness, because it drains into which structure?

cavernous sinus

Through which of the following does the internal carotid artery pass? foramen rotundum/ foramen ovale/ foramen spinosum /foramen magnum/ cavernous sinus

cavernous sinus. The internal carotid artery passes through the carotid canal before taking a convoluted route through the brain, via the cavernous sinus. Other structures that pass through the cavernous sinus include cranial nerves III, IV and the ophthalmic and maxillary branches of V.

Regions of spinal cord

cervical (C1-C7), thoracic (T1-T12), lumbar (L1-L5 - is weak region as undergoes sharp turn), sacral (S1-S5), coccygeal

what is platysma innervated by?

cervical branch of CN VII (facial)

What is Bell's Palsy?

complete destruction of the facial nucleus itself or its branchial efferent fibers (facial nerve proper). Peripheral ipsilateral facial paralysis w/ inability to close the eye on the involved side. Can occur idiopathically; gradual recovery is seen in most cases. Seen as a complication in AIDS, Lyme disease, Sarcoidosis, Tumors, and Diabetes

Skull - anterior view

conchae - help warm and humidify air as it comes in

temporomandiublar joint pic

condyle process of mandible with mandibular fossa with articular disc in between

Pic of dural venous sinuses

confluence of sinuses drain through jugular foramen out of cavity

Auditory apparatus

connection between environment and auditory apparatus. - external parts of ear; look into external auditory meatus with an otoscope

Temporomandibular joint

connection on either side of the head between the temporal bone of the skull and mandibular bone of the jaw. - capsule joint and articular tubercle anteriorly; two actions at temporomandibular joint (hinge action and gliding movement) - can get dislocated jaw from this. to get back in place, push with thumbs on back molar down and back so that head of mandible can get past articular tubercle.

thyroid isthmus

connects the 2 lobes of the thyroid gland - lies over the 2nd and 3rd tracheal rings

Ligamentum flavum

connects the laminae of adjacent vertebrae

interspinous ligament

connects the spinous processes of adjacent vertebrae

Meckel's cave

contains the trigeminal ganglion

tectorial ligament

continuation of the posterior longitudinal ligament up to the foramen magnum

Why can't internal jugular vein be felt easily?

covered by sternocleidomastoid

Foramina in skull

cribiform plate, optic canal, superior orbital fissure, rotundum, ovale, spinosum, internal auditory meatus, jugular foramen, hypoglossal canal

position of optic nerve (cut) in dissection

cut end of optic nerve in skull as passes into eye; can see cut end of optic nerve in base of brain too

Movements of spine

differing regions of spine have different movements due to differing articular facets

tentorial notch dissection

edge of tentorium. important clinically: if have raised ICP above tentorium, the medial part of temporal lobe can herniate around this rigid edge of tentorium, putting pressure on side of the brainstem and causing problems.

Superior rectus contraction does what?

elevates eye and towards midline. *n.b. - this is isolated and not acc in real life.

levator palpebrae superioris

elevates eyelid. Origin: Lesser wing of sphenoid Insertion: Tarsus Innervation: Dual innervation a) Mostly by oculomotor nerve (III) (ie, GSE fibres in the superior division of III)* b) superior tarsal muscle is innervated by sympathetic fibres (smooth muscle) **Why is this clinically important? Horner's syndrome --> ptosis**

conus medullaris

end of spinal cord at L1/L2

Excessive lordosis

exaggerated lumbar curve (sway back)

kyphosis

excessive outward curvature of the spine, causing hunching of the back.

Kyphosis

excessive outward curvature of the thoracic spine, causing hunching of the back.

filum terminale dissection

extension of pia mater. bottom of spinal cord to sacrum that helps anchor spinal cord within dural sheath

denticulate ligaments

extensions of pia mater that secure cord to dura mater

auricle

external ear

Superficial blood vessels in posterior triangle

external jugular vein - main drainage vessel of face. often is indicator about functioning of RHS of heart - pulse seen here is used as clinical imitator of RHS of heart function

two structures sitting on top of sternocleidomastoid in posterior triangle

external jugular vein and CN XI (Accessory nerve) - supplying sternocleidomastoid and trapzeius muscle

disc herniation

extrusion of the nucleus pulposus through the annulus fibrosus of an intervertebral disc

contraction of superior oblique eye muscle results in what movement of eye?

eyes goes out and down. the muscle goes up and turns at a bony protuberance in medial corner of eye and turns back to posterolateral part of orbit

what nerve is platysma innervated by?

facial

Nerve supply of platysma muscle

facial nerve

Stylomastoid foramen

facial nerve (VII)

Which nerve branches under parotid gland?

facial: temporal, zygomatic, buccal, mandibular, cervical

filum terminale

fibrous extension of the pia mater; anchors the spinal cord to the coccyx

What is a suture?

fibrous joints that permit little or no movement

brachiocephalic artery

first branch leaving the aortic arch going anteriorly which divides into the carotid and subclavian arteries

genioglossus muscle

forms the bulk of the tongue and allows it to move freely. Run the tip of the tongue backwards along the floor of the mouth towards the root of the tongue. In the midline is a smooth, firm, rounded ridge formed by the genioglossus muscle running from the genial tubercles of the mandible to the tongue root.

mylohyoid muscle pic

forms the floor of the mouth. depresses mandible and supports tongue

Blowout fracture

fracture of the floor of the orbit - issues of double vision

Common spinal injuries

fractures of atlas, snapping ligaments, dislocation of cervical vertebra. •Spinal cord injury paralyses over 6 people every day •NHS Specialised Spinal Cord Injury Services Annual Statement - in 2017/18, 2429 new patients were referred to the eight specialist centres in England. •This adds to the 50,000 living here that are already paralysed. •Most common causes of spinal cord injury is a broken neck or back as a result of road traffic accidents, accidents during sports or recreation or falls (in older people). •Currently no cure - yet!

insertion of temporalis

from temporal fossa to coronoid process of mandible and anterior ramus of mandible. innervated by trigeminal nerve

bones contributing to the orbit

frontal, zygomatic, maxilla, nasal, ethmoid, sphenoid

Which muscle protracts the tongue?

genioglossus

Which nerve supplies the parasympathetic secretomotor innervation of the parotid gland?

glossopharyngeal (IX) nerve. Submandibular and sublingual gland innervated by mandibular branch of trigeminal nerve and lingual branch from facial nerve which is joined to V3 by chorda tympani

Spinal nerves and vertebrae side view

growth of vertebral column vs spinal cord. vertebral column grows at greater rate and greater extent than spinal cord - so point at which nerves emerge from spine, get progressively further away from where they emerge from spinal cord. so at bottom, nerve has to emerge and travel all the way down to exit. hence below L2 no spinal cord - just bundle of nerves (cauda equina) - where injections or CSF injections taken

What two movements does TMJ do?

hinge and gliding

superior orbital fissure

in sphenoid bone. carries V1 (ophthalmic nerve), CN III, CNIV and CNVI. superolateral to that is optic canal.

coronoid process of mandible

insertion of temporalis

Confluence of the sinuses

intersection of superior sagittal sinus, straight sinus, transverse sinuses, occipital sinus

level of lowest part of 12th rib

Ligamenta flava

lamina to lamina

cisterna magna

large area of cerebrospinal fluid collection between the cerebellum and the medulla. enlarged CSF space at base of brain.

Nasal cavities bones

large number of bones contribute to nasal cavities. - pockets are sinuses in skull; other sinuses are more lateral

scoliosis

lateral curvature of the spine

Scoliosis

lateral curvature of the spine. organs of chest can become compressed with strong curvatures. surgery can be big with screws and nails; or can be more subtle e.g. with corset.

contraction of ciliary muscles causes

lens thickening

lingual tonsil

located at the base of the tongue

palatine tonsil

located on the left and right sides of the throat in the area that is visible through the mouth. label D

where is inferior alveolar nerve derived from?

mandibular branch of trigeminal nerve

Nerve supply of mylohoid muscle

mandibular division of trigeminal nerve

Innervation of buccinator