Head and Neck Anatomy cumulative

Development of the Face

The face is formed by the fusion of five primordia: 1.) Frontonasal Prominence (Single) 2-3.) Maxillary Prominences (Paired) 4-5.) Mandibular Prominences (Paired)

Facial Artery is Toruous

The facial artery is tortuous (twisty) - this gives the artery some laxity, so that when the facial muscles contract and tense the face, the artery does not become taut and constricted, restricting blood flow.

Scalp Arteries from *External* Carotid

- Superficial temporal - Posterior auricular - Occipital

Sella turcica

- Tuberculum sellae - Hypophysial fossa - Dorsum sellae - Posterior clinoid processes

What is Unique about the Optic Nerve?

- not a true a nerve at all, it is a tract of afferent fibers that connects the retina (technically a nucleus of the brain that migrated toward the surface of the head) with the diencephalon. - *really part of the CNS* = an outgrowth of brain - *Surrounded by Meninges* - Nerve fibers within the optic nerves are actually the axons of ganglion cells whose cell bodies are in the retina. Ganglion cell axons leave the eyeball at the optic disc

Root of Neck Nerves

1.) Brachial Plexus 2.) Sympathetic Trunk

Nasocoliary Nerve Branches

1.) Long Ciliary Nerves 2.) Posterior Ethmoid 3.) Anterior Ethmoid 4.) Infratrochlear Nerve

Cartilages of the Larynx

1.) Thyroid 2.) Cricoid 3.) Epiglottis 4.) Arytenoid 5.) Corniculate and Cuneiform

Frontal Recess

A region in the anterior part of middle meatus

Pharyngeal Arches and Cartilage Bar

Each Pharyngeal Arch Has A Transient Cartilage Bar (from neural crest) = Temporary support structures

Facial Muscle Innervation

Facial Nerve (CN VII)

Posterior Triangle Common Pathologies

Parotid tumor

Uncinate (Latin hook-like) Process

Projects upward from the inferior concha

Cochlear Nerve Receptors are in..

Spiral Organ (Organ of Corti)

Innervation of Frontal Sinus

Supraorbital Nerve

Skull

The entire skeleton of the head.

CN IX Glossopharyngeal Nerve Branches

Tympanic Nerve Carotid Branch Pharyngeal Branches Motor branch to Stylopharyngeus Tonsilar Branhces Lingual Branches

Pouch I

Tympanic cavity (middle ear) and pharyngotympanic (auditory or Eustachian) tube

Optic Foramen

carries the *Ophthalmic artery and Optic nerve*

Helix and Antihelix

curved ridges that define the peripheral margins of the auricle

Anterior clinoid process

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Anterior fontanelle

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Articular tubercle

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Clivus

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Condylar Fossa (Paired)

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Coronal Suture

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Dorsum sellae

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External Occipital Protuberance

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External acoustic meatus

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External opening of carotid canal

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Foramen magnum

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Foramen ovale

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Foramen rotundum

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Foramen spinosum

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Frontal Bone

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Groove for greater petrosal nerve

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Groove for lesser petrosal nerve (short and shallow)

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Hypoglossal Canal (Paired)

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Hypophysial fossa

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Internal acoustic meatus

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Internal occipital protuberance

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Jugular fossa

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Lambdoid suture

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Mandibular fossa (part of the temporomandibular joint)

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Mastoid fontanelle

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Mastoid process

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Occipital Bone

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Occipital Condyle (Paired)

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Pharyngeal Tubercle

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Posterior clinoid processes

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Posterior fontanelle

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Sagittal suture

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Sphenoidal emissary foramen (small and inconstant)

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Sphenoidal fontanelle

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Squamous suture

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Styloid process

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Stylomastoid foramen

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Superciliary Arch (Paired)

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Superior and inferior temporal lines

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Superior orbital fissure (paired)

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Supraorbital Margin (Paired)

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Supraorbital Notch/Foramen

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Temporal bone (paired)

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Tuberculum sellae

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Where does the parotid gland empty its contents into the vestibule?

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Zygomatic process

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Internal Carotid Artery (ICA) enters the cranium via...

...the *Carotid Canal* near the midline and traverses the cavernous sinus - Carotid Plexus and Sympathetics to the head from the Superior Cervical Ganglion also go through canal

The pharyngeal arches are transformed into...

...the face and jaw, pharynx, larynx, and ossicles of the middle ear. - Most congenital anomalies in the head and neck region result from faulty transformation of these structures.

Purely Sensory Cranial Nerves

1 = Olfactory 2 = Optic 8 = Vestibulocochlear (hearing and balance) Functional Components: Special Sensory Fibers

Trachea

1" in diameter in adults Extends from the inferior end of the larynx into the thorax "C" shaped hyaline cartilage, with the posterior open ends connected by smooth muscle Common carotid arteries and lobes of the thyroid gland are located lateral to the trachea

Lateral Cervical Cysts

(aka - branchial cysts) usually present along the anterior border of sternocleidomastoid

Carotid Canal

(contains the internal carotid artery and internal carotid autonomic plexus).

Thyroglossal Duct

*A diverticulum of the embryonic pharynx (foregut)* - forms an open connection between initial area of development and final position of thyroid gland. Located exactly mid-line, between anterior 2/3 and posterior 1/3 of the tongue Thyroid gland starts developing in the fetal oropharynx and descends to final position taking a path through the tongue, hyoid bone and neck muscles. The connection between its original position and its final position is the *Thyroglossal duct* - This duct normally atrophies and closes off as the *foramen cecum* before birth but can remain open in some people

Pterygopalatine Fossa (PPF) Bony Borders

*Anterior*: posterior surface of the maxilla *Posterior* Pterygoid process & greater wing of the sphenoid *Medial*: perpendicular plate of the palatine bone *Lateral*: open to the infratemporal fossa via the pterygomaxillary fissure *Superior*: body of the sphenoid bone *Inferior*: the anterior and posterior walls slope towards each other inferiorly, but don't quite meet - the gap between the walls communicates below with the greater palatine canal

PPF: Communications With Other Regions of the Head

*Anterior*: the inferior orbital fissure opens into the orbit *Posterior*: foramen rotundum opens high on the posterior wall, connecting to the middle cranial fossa; the pterygoid canal opens a bit lower, connecting to the carotid canal. Posteromedially, a small palatovaginal canal communicates with the nasopharynx *Medial*: the sphenopalatine foramen, high on the medial wall, opens into the nasal cavity *Lateral:* the pterygomaxillary fissure opens into the infratemporal fossa *Inferior:* the greater palatine canal communicates with the palate. It bifurcates below, opening onto the hard palate via greater and lesser palatine foramina

Swallowing (Deglutition): Stage 3

*Involuntary* Sequential contractions of all 3 constrictors that force the bolus into the esophagus

Tooth Surfaces

*Occlusal*: comes into contact with the occlusal surface of an opposing tooth during chewing *Mesial*: facing to the center of the dental arch *Distal*: facing the end of the dental arch *Facial (or Buccal)*: facing the lips and teeth *Lingual*: facing the tongue

Innervation of the Lacrimal Gland

*Parasympathetic!!* innervation by Facial Nerve (CN VII)

Submandibular Sub-Triangle Contents

- *Submandibular salivary gland* (fills most of the triangle) - *Submandibular lymph nodes*: receive lymph from anterior tongue and the oral cavity - *XII*: passes between mylohyoid and hyoglossus muscles; occipital artery twists around it - *Nerve to mylohyoid (V3)*: from ITF to innervate digastric anterior belly and mylohyoid - *Lingual artery*: is passing through - *Submandibular duct*: on the lateral surface of the hyoglossus muscle and is crossed by the lingual nerve (as heads toward the tongue) - *Parts of facial artery and vein; submental artery* (branch of facial artery)

Autonomic Ganglia: CN vs Spinal Nerves

- Some Cranial nerves associate with *Parasympathetic ganglia* - Spinal nerves associate with *Sympathetic ganglia* (S goes with S)

Pharyngeal Arches Mnemonic - Arch 1

"*M*ake Some Important Shtuff" Nerve: *M*andibular (V3) Artery: Mesoderm: *M*astication Neural Crest: *M*axilla, *M*andible, *M*alleus, Incus Pouch: *M*iddle Ear

Calvaria

"Skull cap" - the upper "lid" of the skull.

Platysma Muscle

"grimace muscle"

Pharyngeal Arches Mnemonic - Arch 2

"pharyngeal arches Make *S*ome Important Shtuff" Nerve: *S*mile: VII (Facial n) --> also innervates *S*ubmandibular and *S*ublingual glands Artery: Mesoderm: *S*mile (Facial Expressions), *S*tapedius Neural Crest: *S*tapes, *S*tyloid, Upper Body and Lower Horn of Hyoid (See hyoid card)

Pharyngeal Arches Mnemonic - Arch 3

"pharyngeal arches Make Some *I*mportant Shtuff" Nerve: *I*X (Glosso*pharyngeal*) Artery: *I*CA Mesoderm: Stylo*pharyngeus* Neural Crest: Pouch: *I*nferior Parathyroid and Thymus (Thymus is *I*mportant), Upper Horns and Lower Body of Hyoid (see hyoid card)

Pharyngeal Arches Mnemonic - Arch 6

"pharyngeal arches Make Some Important *Sh*tuff" Arch 4+6: Shared = Sh; but 4 is above 6, it comes first and wants first pick Nerve: 4+6 = 10 (X) X *R*ecurrent Laryngeal nerve [4 picks first it picks the best (superior) 6 gets the *R*est] Artery: Pulmonary Artery, Ductus Arteriosus Mesoderm: Larynx except Cricothyroid Neural Crest: Other Cartilage

Pharyngeal Arches Mnemonic - Arch 4

"pharyngeal arches Make Some Important *Sh*tuff" Arch 4+6: Shared = Sh; but 4 is above 6, it comes first and wants first pick Nerve: X Superior Laryngeal n [4 picks first it picks the best (superior) ] also 4+6 = 10 (X) Artery: Aortic Arch, Right Subclavian Mesoderm: Cricothyroid Neural Crest: Thyroid Cartilage (Cricothyroid and Thyroid Cartilage are big things, so 4 picks them bc it wants the best, gives 6 the rest) Pouch: Superior Parathyroid (still picking the best parts)

Pharyngeal Arches Mnemonic

"pharyngeal arches Make Some Important Shtuff: Arch 1: M Arch 2: S Arch 3: I Arches 4+6: Sh (Arch 5 degenerates)

Superior Cervical Ganglion

"the end of the road" of the sympathetic trunk Lies opposite *C2* Several carotid nerves are given off the ganglion, which ramify about the carotid arteries, forming *internal and external carotid plexuses*

Roots of the Brachial Plexus in Posterior Triangle

(C5-T1): exit between anterior and middle scalene muscles and descend between the 1st rib, clavicle, and superior scapula to enter the axilla. The roots will form trunks (upper, middle, and lower). *Branches* - Suprascapular nerve (off upper trunk): supraspinatus and infraspinatus muscles - Dorsal scapular nerve (off C4-5 roots): levator scapulae, rhomboid major, and rhomboid minor muscles - Long Thoracic nerve (off C5-7 roots): serratus anterior muscle

Pterygoid hamulus

(acts as a pulley for the tendon of the tensor veli palatini muscle)

Trigeminal Neuralgia

(also known as Tic douloureux, due to the facial twitches that accompany the disorder) Neurologic condition affecting the trigeminal nerve that presents as extreme, sporadic, and sometimes incapacitating attacks of facial pain. Usually unilateral and typically occurs in the areas of the face served by the *maxillary (V2) or mandibular (V3) branches of V* May be triggered by simple things: brushing teeth, shaving, talking, or chewing, or it may occur spontaneously. Current research suggests that in many cases the cause is compression of the main trunk of the trigeminal nerve near the pons by a blood vessel.

Jugum

(articulates with the ethmoid bone)

Carotid Sinus

(baroreceptor): at bifurcation; innervated by CN IX (carotid sinus nerve) ("sinus pressure" carotid sinus detect pressure changes)

Root of the Neck

(base of the neck, cervicothoracic region) Important because it is the region of continuity between the neck and thorax and the neck and upper limbs

Pterygoid fossa

(between the plates)

Long Ciliary Nerves

(branches off the nasociliary nerve) enter the eyeball. These nerves carry sympathetic fibers to the dilator pupillae muscle of the iris and also carry sensory fibers from the cornea. These sensory fibers from the cornea are the afferent limb of the corneal reflex.

The Pharyngeal Apparatus

(branchial apparatus) forms in the neck region during the 4th week of development. Has 4 components: A. Pharyngeal arches B. Pharyngeal pouches C. Pharyngeal clefts (grooves) D. Pharyngeal membranes

Carotid Body

(chemoreceptor): medial side of the bifurcation; innervated mainly by the carotid sinus nerve (and by X)

Lobule

(ear lobe) is the fleshy inferior part of the auricle. It holds the distinction of being the only part of the auricle not supported by cartilage. It consists of skin and connective tissue

Parietal foramen

(inconstant = for an emissary vein)

Occipital Arteries

(off external carotid artery) - Crosses the apex of the posterior triangle to serve the posterior ½ of the SCALP

Transverse/Superficial Cervical Arteries

(off the thyrocervical trunk of subclavian artery) - Across the anterior scalene muscle and phrenic nerve ~2cm superior to the clavicle - Dorsal scapular branch accompanies the dorsal scapular nerve; it may arise independently from the subclavian artery

Sphenoidal sinus

(paired but rarely symmetrical - see the hemiskull)

Sutures

(sutures are a type of fibrous joint) - Coronal suture - Sagittal suture - Lambdoid suture - Squamous suture Most of the remaining sutures are named by joining the names of the adjacent bones together (e.g., zygomaticotemporal, frontonasal, etc.). - Sutural bones (Wormian bones) may be present within the sutures themselves.

Opthalmic Artery

(the first large branch of internal carotid) passes through the optic foramen and canal to enter the orbit. It may pass above or below the optic nerve

Tonsillar Bed

(the space between the pillars) Formed by the superior pharyngeal constrictor and a thin fibrous sheet of the pharyngobasilar fascia (blends with the periosteum of the cranial base)

Anterior Jugular Veins

(usually a left and a right) Begin below the chin in the superficial fascia and pass inferiorly just lateral to the midline. They duck under the SCM and pass laterally to enter the EJVs. - Communicate through the anterior jugular arch that passes across the midline of the neck just above the manubrium. If present, it could cause bleeding problems during a tracheotomy procedure

Suprascapular Arteries

(usually off thyrocervical trunk, or off subclavian artery) - Passes inferolaterally across the anterior scalene and phrenic nerve, then posterior to the clavicle to serve the scapula and associated muscles

Cervical Plexus in Posterior Triangle

(ventral rami C1-4) *Phrenic nerve (C3, 4, 5)*: originates from the C3-5 cervical plexus roots and crosses the anterior surface of the anterior scalene muscle (it is also in the anterior triangle) - Motor, sensory, and sympathetic fibers; forms at the superior border of the thyroid cartilage (~C4), and lies deep to the prevertebral fascia *Accessory phrenic nerve (contribution from C5)*: if present, it lies lateral to the main nerve and descends posterior to the subclavian vein - Sensory (Erb's point) & motor (ansa cervicalis )

4 Functional Mechanisms of the Ear that Allow us to Collect and Perceive Sounds

1.) Collecting Sound Waves 2.) Amplifying Sound 3.) Transduction of Vibrations into Action Potentials 4.) Transmission of Action Potentials to the Brain

Semicircular Canals

3 interconnected canals (anterior, posterior, and lateral), each oriented at right angles to one another

Digastric Muscle

Anterior and posterior bellies joined by a tendon that glides in a fibrous sling at the greater horn of the hyoid - Anterior belly: nerve to mylohyoid (from V3) - Posterior belly: VII

All Facial Muscles are Derived from....

*2nd pharyngeal arch* - thus *Facial nerve (VII) branches* innervate them. - Also derived from this mass are the platysma muscles, located in the superficial fascia of the neck, whose chief functions are to draw the angles of the mouth downward and to tense the skin of the neck.

Thyroid Tumors

Benign (adenomas that secrete thyroid hormone) Malignant (rare)

CN XI and the Posterior Triangle

CN XI crosses the posterior triangle of the neck and is vulnerable to injury here.

Embryology of the Larynx

*4th and 6th pharyngeal arches*: mesenchyme at the upper end of the laryngotracheal tube - 2 *Arytenoid Swellings*: convert the primitive glottis into a T-shaped opening that becomes reduced to a narrow slit Ventricles form, and the mucous membrane above and below the ventricles become the vestibular folds and vocal folds, respectively

External Ear

*Auricle*: Collects sound waves *External acoustic Meatus* directs captured sound waves inside the head *Tympanic membrane*: Separates external acoustic meatus from middle ear, sound waves cause it to vibrate

Incus ("Anvil")

*Body*: rounded, articulates anteriorly with head of Malleus *Long process* projects inferiorly, behind and parallel to the handle of the malleus (where its shadow can sometimes be seen) *Lenticular process*, short round projection that extends away from the long process and it articulates with the head of the stapes *Short process projects* posteriorly and is attached to the posterior wall of the tympanic cavity by a ligament

Sella turcica (as part of the Middle Cranial Fossa)

*Boundaries* - anterior and posterior clinoid processes *Parts* - Tuberculum sellae - Hypophysial fossa - Dorsum sellae *Content* - Hypophysis (pituitary gland) *Foramen*: Jugular Foramen, Hypoglossam Foramen

Cutaneous Nerves: Trigeminal V1

*Branches of Frontal Nerve: Supratrochlear and Supraorbital Nerves* *Branches of Nasociliary Nerve: Infratrochelar and External Nasal Nerve* forehead, upper eyelid, and dorsum of nose

Cutaneous Nerves: Trigeminal V2

*Branches of Zygomatic: Zygomaticotemporal and Zygomaticofacial Nerves* lower eyelid, infra-orbital region, temporal region, and sides of the nose

Cutaneous Nerves: Trigeminal V3

*Buccal Nerve* chin, lower lip, cheek, and temporal region

Thyrohyoid (Innervation)

*C1* by hitching a ride on XII - Runs superiorly from the oblique line of the thyroid cartilage to the hyoid

Isthmus of the Fauces

Connection between the oral cavity proper and the oropharynx Bounded anteriorly by the palatoglossal folds and posteriorly by the palatopharyngeal folds - Between the two folds lie the tonsillar fossae containing the palatine tonsils, masses of lymphoid tissue commonly referred to as "tonsils"

A Lesion of CN III will cause what in the tongue?

Deviation to the side of the lesion when sticking the tongue out

Chorda Tympani

*Carries taste information from the anterior 2/3 of the tongue and preganglionic parasympathetic fibers to the submandibular ganglion* 1.) Arises from the *Facial Nerve* just above Stylomastoid Foramen and runs superiorly through a bony canal in the temporal bone to enter the tympanic cavity from its posterior wall 2.) Runs across the tympanic membrane from posterior to anterior, where it also passes between the handle of the malleus and the long process of the incus Leaves the tympanic cavity through a tiny slit in its anterior wall, the *Petrotympanic fissure* to enter the infratemporal fossa, where it *joins the lingual nerve*

Transduction of Vibrations into Action Potentials

*Cochlea* of the internal ear is a transducer that converts vibrations of fluid into action potentials in the *Cochlear nerve*

Transmission of Action Potentials to the Brain

*Cochlear part of the vestibulocochlear nerve (CN VIII)* delivers the action potentials to the brain where sound it is perceived and interpreted

Innervation of the Larynx

*Cranial Nerve X (Vagus)* 1.) Superior Laryngeal - External Branch (Motor) - Internal Branch (Sensory and Autonomic) 2.) Inferior LAryngeal

Tooth Anatomy

*Crown*: part visible above the gingiva and is covered by enamel *Root*: fixed in the tooth socket by the peridontium, their number varies *Neck*: between the crown and root - Each tooth is contains a cavity that is filled with pulp and the extension of pulp into the root is the root canal

Openings for Anterior and Posterior Ethmoidal Nerve

*Ethmoidal Nerve (branches of nasociliary) and Posterior Ethmoidal Vessels* - These nerves supply sensation to the ethmoid and sphenoidal air sinuses

Scala Vestibuli and Scala Tympani

*FILLED WITH PERILYMPH!!!!* Because of its central location, the cochlear duct (containing *Endolymph*) subdivides the cavity of the cochlea into 2 *Perilymph-filled channels*: - Scala vestibuli above cochlear duct - Scala tympani below cochlear duct

Parotid Innervation

*Facial Nerve (CN VII)* Facial nerve enters the parotid and divides into *5 branches* within the gland: 1.) Temporal 2.) Zygomatic 3.) Buccal 4.) Mandibular 5.) Cervical These emerge onto the face to supply the mimetic muscles. Removal of the parotid thus requires meticulous surgical dissection.

CN IX Glossopharyngeal Nerve Functional Components

*General sensory*: Mucous membranes of middle ear, pharynx, and posterior 1/3 of tongue. *Special sensory*: Taste posterior 1/3 of tongue. *Visceral sensory*: Baroreceptor (carotid sinus) & chemoreceptor (carotid body) *Visceral motor (parasympathetic)*: Innervates parotid gland *Skeletal motor*: Stylopharyngeus m.

Innervation of the Palate

*Greater palatine nerves*: emerge from the greater palatine foramen and supplies the hard palate *Nasopalatine nerves*: emerges from the incisive fossa and innervates the anterior hard palate (the four incisors) *Lesser palatine nerves*: supply the soft palate

Malleus ("Hammer")

*Head*:round, articulates with the incus *Handle* passes downward to attach to the tympanic membrane *Anterior process* connects to the anterior wall of the tympanic cavity by a ligament *Lateral process*: attached to the tympanic membrane (producing the mallear prominence and mallear folds)

Stapes ("Stirrup")

*Head*:very small, articulates with the long process of the incus *Neck*: just distal to the head, receives the attachment of the stapedius muscle *2 Limbs*: attach the neck to the base Edge of the *Base* ("Footplate") attach to the margins of the oval window by a ring of connective tissue called the *annular ligament*

Arterial Supply to the Larynx

*Inferior laryngeal artery*: primary supply to structures in the inferior larynx *Superior laryngeal artery*: accessory supply to the superior part of the larynx

Pterygopalatine Fossa (PPF) Location

*Inferior* to the "apex" of the orbit *Anterior* to the middle cranial fossa *Posterior* to the maxillary sinus *Lateral* to the nasal cavity *Medial* to the infratemporal fossa

Larynx Internal Spaces (Superior to Inferior)

*Inlet/aditus*: between the aryepiglottic folds *Vestibule*: between aditus and vestibular folds *Ventricle*: lateral recesses between the vestibular and vocal folds - End in blind pouches called saccules *Infraglottic cavity*: between vocal folds and inferior border of cricoid cartilage *Glottis*: vocal folds + rima glottidis, the space between vocal folds

Trapezius muscle

*Innervation: CN XI* Attachments: superior nuchal line, external occipital protuberance, nuchal ligament, and spinous processes C7-T12 - Elevates, retracts, and rotates the scapula superiorly. *Posterior boundary of the posterior triangle*

Innervation of the Nasal Septum

*Internal Nasal Nerve* from the anterior ethmoidal, off V1. *Nasopalatine Nerves* branching from the Pterygopalatine Ganglion, from V2, pass through the incisive foramina anteriorly and also supply the mucosa of the hard palate

Swallowing (Deglutition): Stage 2

*Involuntary and rapid* Soft palate elevates, sealing off the nasopharynx Pharynx widens and shortens as the suprahyoid and longitudinal pharyngeal muscles contact, elevating the larynx

Respiratory Layer

*Larynx* - Located between (C4-C6) - Easily palpated - Complex organ of voice production *Trachea* - Extending from larynx (C6 ) to right and left main bronchi - Tracheal cartilages 2-4 usually covered by isthmus

Superior Laryngeal Nerve - External Branch

*Motor* Descends posterior to the sternothyroid with the superior thyroid artery. It lies on the inferior constrictor muscle and pierces it. Supplies: *Inferior constrictor and Cricothyroid*

Tensor Tympani Origin and Insertion

*Origin*: from the bony wall of its canal (the canal opens on the anterior wall of the tympanic cavity) as well as from the cartilage of the pharyngotympanic tube *Insertion*: the tendon turns laterally around the processes cochleariformis to attach to the handle of the malleus dampens sound by tensing tympanic membrane

Stapedius Origin and Insertion

*Origin*: from the internal bony walls of the pyramid (on the posterior wall of the tympanic cavity) *Insertion*: the tendon emerges from the apex of the pyramid to attach to the neck of the stapes

CN V does *NOT* convey what type of fibers from the brainstem?

*PREganglionic parasympathetic fibers* - [Remember: CNs III, VII, IX and X are the cranial part of the craniosacral (parasympathetic) outflow!] - Postganglionic parasympathetic fibers simply hitch rides on branches of V1, V2, and V3 to their destinations (e.g., lacrimal gland and salivary glands) When we think of CN V we should think "major sensory nerve of head," as well as muscles of mastication (V3 only)+ mylohyoid and ant belly digastric. Therefore, we are thinking sensory and motor. For is to have pre-ganglionic we would be thinking parasympathetic or sympathetic, but we know there is no PS or Sympathetic done by 5.

Third part of maxillary artery

*Pharyngeal artery* *Artery of the Pterygoid canal* *Descending Palatine artery* *Sphenopalatine artery* PADS (or PAPS) (Max the 3rd wears PADS to protect himself from possible Pterodactyl attack)

Tympanic Membrane Innervation

External surface: Auriculotemporal nerve and auricular branch of the vagus. Internal surface: Glossopharyngeal nerve

Pharyngeal Constrictors

*Pharyngobasilar fascia*:strong internal fascia *Buccopharyngeal fascia*: thin external fascial lining *Innervation*: Pharyngeal plexus of nerves - Contract involuntarily from superior to inferior - Have gaps that allow for structures to enter or leave the pharynx

Digestive Layer

*Pharynx* *Cervical Esophagus* - Upper 1/3 - Striated (voluntary muscle) - Between the trachea and cervical vertebrae - Continuous with the pharynx

Superior Cervical Ganglion

*Postganglionic sympathetic nerve fibers* derived from the superior cervical ganglion of the sympathetic trunk supply: -sweat glands - arrector pili muscles - blood vessels in the facial skin

PPF: Communications With Other Regions of the Head *Lateral*

*Pterygomaxillary Fissure* opens into the infratemporal fossa

Deep cervical/Prevertebral muscles

*Scalenes: anterior, middle, & posterior; longus capitis, and longus colli* Flex the head and neck anteriorly and laterally Attach to the upper ribs, where some act as accessory inspiratory muscles by elevating the ribs. Location: just anterior and lateral to the vertebral column, posterior to the viscera of the neck.

Parathyroid Gland Function

*Secrete parathyroid hormone* 1.) Increases blood Ca levels - Stimulates osteoclasts to break down bone and release Ca - Increases GI Ca absorption 2.) Antagonist to Calcitonin

Superior Laryngeal Nerve - Internal Branch

*Sensory and Autonomic* Pierces the thyrohyoid membrane (with superior laryngeal artery) Sensation to the mucosa *above the vocal fold*

PPF: Communications With Other Regions of the Head *Medial*

*Sphenopalatine Foramen*, high on the medial wall, opens into the nasal cavity

Vocalis Muscle (Deep/Medial part of Thyroarytenoid)

Fine movement of Vocal Ligament

Diaphragma Sellae

Fold of meningeal dura forming the roof over the pituitary gland Has a small gap for the stalk/infundibulum of the pituitary gland

Development of the Parathyroids

*Superior parathyroids derived from pharyngeal pouch IV Inferior parathyroids from pharyngeal pouch III* - Topographically, doesn't make sense until you factor in that the thymus (a thoracic organ) is also derived from pharyngeal pouch III. Because the parathyroid descend from the embryonic pharynx, it is common for them to have ectopic definitive locations.

4 Branches of the Subclavian Artery

*Vertebral Artery* *Thyrocervical Trunk* - Suprascapular a - Transverse Cervical a - Inferior Thyroid a *Internal Thoracic Artery* *Costocervical Trunk* - Highest Intercostal a - Deep Cervical a "Very Thick Interns Cost" (are costly)

Swallowing (Deglutition): Stage 1

*Voluntary*. Food bolus is compressed against the palate and pushed into the oropharynx (mainly by muscles of the tongue/soft palate)

Nasopalatine Nerve

From: Pterygopalatine ganglion (Branches of V2) To: *Nasal Septum and Hard Palate*

Lesser Palatine Nerve

From: Pterygopalatine ganglion (Branches of V2) To: *Soft Palate*

Roof of Orbit Bones

Frontal Bone

Third Arch Aortic Arch Artery

Gives rise to the left and right common carotid arteries, as well as the proximal portions of the internal carotid arteries.

Septal Perforation

Hole through the cartilaginous nasal septum. Man be a result of infection, nasal piercings, surgery, nasal steroid sprays and cocaine Symptoms vary and are more serious the closer to the nostrils. Surgery can be attempted with varying degrees of success.

Musculotubal canal

In the living it contains the tensor tympani muscle and the pharyngotympanic (auditory) tube

2 Surfaces of Tongue

Inferior - rests against the floor of the mouth Dorsal - more extensive, superior and posterior surface

Laryngeal Muscle Innervation

Inferior Laryngeal and External Laryngeal Nerves

Internal Jugular Vein (IJV) Tributaries

Inferior petrosal sinus, facial, lingual, pharyngeal, and superior thyroid veins

Petrous part of temporal bone: Superior View

Internal acoustic meatus Groove for greater petrosal nerve Groove for lesser petrosal nerve (short and shallow)

Development of Sinuses

Keep growing and growing throughout the life span

Laryngeal Inlet

Laryngopharynx communication with the larynx

Upper Opening in the Tympanic Cavity (Middle Ear) Anterior Wall

Leads into a bony canal that contains the *tensor tympani muscle*. This canal is separated from the pharyngotympanic tube by a thin bony shelf.

Structures that enter or leave the pharynx: *Superior to the superior pharyngeal constrictor*

Levator veli palatine (LVP) Pharyngotympanic tube Ascending palatine a.

Facial Landmarks

Lips Angle of the mouth Philtrum Nasolabial sulcus Nose: nares, ala, apex, root, dorsum

Vocal Fold

Mucosa covered vestibular/vocal ligament

Orbicularis Oculi

Muscle that surrounds the orbit and closes the eyelids - A muscle of facial expression - Innervated by *CN VII (facial)* - In diseases of the facial nerve (Bell's palsy, CVA), the eye may not close properly

Tympanic Cavity (Middle Ear) Contents

- Air-filled space in *petrous temporal bone* lined by mucous membrane - 3 Ossicles (malleus, incus, stapes) - 2 tiny skeletal muscles (tensor tympani, stapedius) - Chorda tympani n. (CN VII) - Tympanic plexus of nerves

First Arch Divides into...

- Cranial Maxillary prominence/process : future Upper Jaw - Caudal Mandibular prominence/process: future Lower Jaw

External Nose

- Dorsum - Root - Tip - 2 Alae - 2 Anterior Nares (nostrils), separated by the mobile *Nasal Septum (Columella nasi)*

Scalp Trigeminal Nerves Alternate View

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Meningeal Layers in the cranial cavity, from superficial to deep

- Dura mater: the tough outer fibrous layer - Arachnoid mater: the middle thin layer - Pia mater: the delicate inner layer, directly covering the cerebrum

Pilomotor Fibers

Postganglionic Sympathetic nerve fibers to Arrector Pili Muscles

Special Relationships: Superficial to the Hyloglossus

- Hypoglossal nerve (CN XII) - Lingual nerve and submandibular ganglion - Submandibular salivary duct

Special Relationships: Deep to the Hyloglossus

- Lingual artery - Glossopharyngeal nerve (CN IX)

Anterior View of Sphenoid Bone

Pterygoid Ppocess PP Fossa Pterygoid Canal Foramen Rotundom

Pterygoid Process Medial plate

Pterygoid hamulus (acts as a pulley for the tendon of the tensor veli palatini muscle)

Wrinkles

Pull of underlying muscles produces wrinkles and creases in the facial skin. Normal aging due to loss of collagen and elastic fibers in the dermis can cause these to become more noticeable or permanent, especially around the mouth, eyes ("crow's feet"), and on the forehead ("worry lines"). Aging of the skin can be accelerated by overexposure to the sun and by long-term smoking.

Muscles derived from Second Arch Mesenchyme

- Muscles of facial expression (mimetic muscles) - Stylohyoid - Posterior belly of the digastric - Stapedius (middle ear)

Muscles derived from First Arch Mesenchyme

- Muscles of mastication (chewing muscles) - Mylohyoid - Anterior belly of the Digastric - Tensor tympani (middle ear) - Tensor veli palatini (soft palate)

Round Window (fenestra cochlea).

Second opening into the internal ear Closed by the secondary tympanic membrane - Below the promontory

Muscles derived from 4th and 6th Arch Mesenchyme

- Pharyngeal constrictor muscles (swallowing muscles) - Intrinsic muscles of the larynx (muscles of phonation = sound production) - Levator veli palatini (soft palate) - Palatoglossus (palate + tongue) - Muscle of upper esophagus

Hutchinson's Sign

Shingles (Herpes Zoster) in the distribution of V1 - Herpes Zoster at V1 can lead to blindness as it can impact the cornea - Ophthalmologic Emergency!

Sinus Drainage

Sinuses generally have openings for drainage into the nasal cavity. Note the specific drainage of these sinuses is quite variable.

Scalenus Posterior

Small, it inserts on the second rib

Foramen Rotundom MRI

Sphenoid Sinus Masticator Space Foramen Rotundum

Petrous part of temporal bone: Inferior View

Styloid process Stylomastoid foramen Mastoid process External opening of carotid canal Musculotubal canal - In the living it contains the tensor tympani muscle and the pharyngotympanic (auditory) tube Jugular fossa

Lymphatic Drainage of the 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

Topography of Parathyroid Glands: A Paradox?

Superior parathyroid --> From 4th pharyngeal pouch Inferior parathyroid --> From 3rd pharyngeal pouch (not sure why this is a paradox????)

Thyroid Blood Supply

Superior thyroid artery (from the external carotid) Inferior thyroid artery (from the subclavian artery) - These vessels anastomose freely within the gland - Sometimes a thyroid ima artery (branch of the brachiocephalic artery OR aorta), passes upward to the isthmus

Suprascapular Nerve

Supplies the supraspinatus and infraspinatus muscles of the scapula

Subclavian (3rd part) Arteries

Supplies upper extremity Starts about a finger's breadth superior to the clavicle opposite the anterior scalene. It lies posterior to the subclavian vein in the omoclavicular triangle. You can feel it in this triangle, and can *control bleeding in the upper extremity*.

Deep Fascia of the Neck (Purpose)

Supports the viscera, muscles, vessels, and deep lymph nodes - Allows neck structures to move and glide past one another without difficulty (e.g. pass bolus down the pharynx, or when turning your head) - Boundaries of compartments and barriers to prevent the spread of infection or abscesses. A specific compartment may be opened by incision and drained - Fascial layers may be separated by pus or fluid accumulation, creating a connection where an infection may spread to another body region (e.g. to the mediastinum) - Natural cleavage planes used as guides during dissection and exposing surgical fields

Cancers originating from thoracic or abdominal organs can involve supraclavicular nodes

Supraclavicular nodes have connections with lymphatic vessels that drain the upper limb (via axillary nodes) and the mediastinum and lungs (via tracheal nodes and connections to the bronchomediastinal lymph trunks), as well as those that drain the scalp, head, and neck Lymph from abdominal organs can make its way to the supraclavicular nodes via connections to the thoracic duct on the left side of the body --> may be involved with carcinoma originating anywhere in the head and neck, and within the thoracic and abdominal cavities

Rhinoplasty

Surgical reshaping of the nasal cartilages, usually performed for cosmetic reasons

Cricothyroid Muscle

Tenses Vocal Ligament

Inferior Laryngeal Nerve

Termination of the recurrent laryngeal nerve - Runs in the laryngeo-tracheal (tracheoesophageal) groove -o Enters the larynx by passing deep to the inferior border of the inferior constrictor muscle, and divides into anterior and posterior divisions that travel with the inferior laryngeal artery - Supplies the *rest of the skeletal muscles* - *Sensory from the true vocal fold and structures Inferiorly into the trachea*

Auriculotemporal Nerve

The auriculotemporal nerve, a branch of V3, passes deep to the Parotid gland on its way to the scalp. *Postganglionic parasympathetic secretomotor fibers from CN IX* supply the parotid by hitching a ride with the auriculotemporal.

Diploe

The central layer of spongy bone between the two layers of compact bone (external and internal tables) of the flat cranial bones.

Special Relationships: Course of the Lingual Nerve

- Proximally, lateral to the duct - Distally, medial to the duct

Lymphatic Drainage of the Face

- Submental Nodes - Submandibular Nodes - Parotid Nodes - Posterior Auricular Nodes - Occipital Nodes

External Jugular Vein

The only constant tributary of the subclavian vein is the EJV Transverse Cervical and Suprascapular veins usually join the EJV - Vertebral Vein is a tributary of the Brachiocephalic Vein. Note however that the vertebral vein DOES NOT receive blood from the cranial cavity

Sinus Imaging

The sinuses can be visualized on skull radiographs (from a Water's view) or, more commonly, a CT scan of the sinuses. - Healthy sinuses appear as dark (air-filled) spaces (Left) - When infected they become *thickened and/or fluid-filled, and appear as opacities* (Right)

Dorsal Scapular Artery

The transverse cervical and suprascapular arteries do nothing in the neck; they supply structures in the shoulder and back. The *transverse cervical artery usually divides into superficial and deep branches*. A common variation occurs when the *deep branch arises directly from the subclavian artery* (usually the third part). This branch is then called the *Dorsal Scapular Artery*. A small transverse cervical artery may or may not remain as a branch of the thyrocervical trunk in this case. The suprascapular artery may also be displaced to the third part of the subclavian.

Lacrimal Sac

Upper dilated end of the nasolacrimal duct - lodged in a deep groove formed by the lacrimal bone and frontal process of the maxilla Connects the lacrimal canaliculi, which drain tears from the eye's surface, and the nasolacrimal duct, which conveys this fluid into the nasal cavity

Medial Nasal Prominences Fuse

Upper portion forms the dorsum and septum of the nose Lower portion forms the *Intermaxillary segment*, which gives rise to: 1.) Philtrum of the upper lip 2.) Premaxilla (the region of the maxilla anterior to the incisive foramen) 3.) Upper incisor teeth and their associated gingivae (gums)

CN X

Vagus Nerve Supplies external ear, pharynx, larynx, thoracic organs, and abdominal organs as far distal as the left colic flexure. - Efferent limb of "gag" reflex - Muscles of phonation - Cardiac muscle - Smooth muscle and glands of foregut & midgut organs - Visceral sensations from organs

CN IX Glossopharyngeal Nerve Visceral Sensory Component

Visceral sensory fibers supply the carotid sinus and carotid body - both located near the bifurcation of the common carotid artery into external and internal carotid arteries. Sensory fibers from the sinus and the body are transmitted via the carotid branch of IX (aka = nerve of the carotid sinus; Hering's nerve).

External Acoustic Meatus Wall

Wall = 1/3 cartilage, 2/3 bone Lined by skin with hairs and ceruminous glands

Organ of Corti

Where the hearing receptor cells are found Stimulation of the receptors produces action potentials in neurons of the *Cochlear division of the Vestibulocochlear nerve (CN VIII)* - These are bipolar neurons with cell bodies in the Cochlear Ganglion (spiral ganglion)

Vestibule

a spherical cavity with the oval window in its lateral wall; Communicates with the semicircular canals and the cochlea

Paranasal Sinuses are lined by...

a thin mucosal membrane (which may become infected --> sinusitis)

Pterygoid process (paired)

a. Medial plate - Pterygoid hamulus (acts as a pulley for the tendon of the tensor veli palatini muscle) b. Lateral plate c. Pterygoid fossa (between the plates)

Thyroid Cartilage Oblique Line

attachment for the sternothyroid and thyrohyoid muscles

Oral Cavity

consists of two parts, the oral vestibule and the oral cavity proper

Geniculate Ganglion

contains cell bodies of afferent neurons in VII that carry taste and skin sensations.

Sacapha

curved groove between the helix and antihelix

Pharyngeal Arch Mesenchyme

derived from *paraxial mesoderm* = gives rise to skeletal muscles.

Pouches III and IV have...

dorsal and ventral portions

Opthalmic Veins (Superior and Inferior)

pass through the orbit, connecting the angular vein to the *Cavernous Sinus*

Inferior Oblique of Eye

passes posterolaterally below the inferior rectus Innervation is by CN III

Nasopalantine Nerve

passes through the sphenopalatine foramen, hops across the body of the sphenoid bone, and then passes obliquely across the nasal septum - Sensory to a good portion of the *nasal septum*, then sends its terminal portion through the incisive foramen to supply the *anterior part of the hard palate and related gingivae*

Axial Head MRI

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Cranial Nerves Exiting Skull

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Pharyngeal Nerve

sensory to the upper nasopharynx, via the palatovaginal/pharyngeal canal

Accessory Nerve

serves the SCM before it emerges 1/3 down its border - Passes postero-inferiorly through the triangle within or deep to the investing fascia, on the prevertebral fascia of the levator scapula muscle - Vulnerable in the roof of the posterior triangle Lesions of CN XI may be caused by penetrating trauma, surgical error, or compression of the nerve leaving the cranial cavity. Hallmark sign of trapezius damage: "drooped shoulder"

Cochlea

spiral canal shaped like a snail's shell. It makes two and one-half turns around a central bony core called the modiolus. The round window is located in the lateral wall of the base (first turn) of the cochlea

Straight Sinus

superior margin of tentorium cerebelli at the attachment of the falx cerebri; ends posteriorly in the confluence of sinuses

Torus of the Pharyngotympanic (PT) Tube

the cartilaginous portion of the tube

Soft Palate

the movable posterior 1/3 of the palate. It is reinforced by the palatine aponeurosis and contains 5 muscles: 1. Tensor veli palatini (TVP) 2. Levator veli palatine (LVP) 3. Palatoglossus 4. Palatopharyngeus 5. Musculus uvulae All are innervated by CN X with the exception of the TVP (CN V3)

Nasolacrimal Duct

~1.5 cm long Descends posteroinferiorly and laterally in a bony canal and eventually opens into the inferior meatus of the nasal cavity - That's why, when you cry, your nose runs!

Ethmoid Bone

1. Crista galli 2. Cribriform plate 3. Cribriform foramina 4. Perpendicular plate 5. Ethmoidal labyrinth (Lateral mass) (paired) a. Superior and middle nasal conchae [Project into the nasal cavities] b. Orbital plate [Located in the medial wall of the orbit] c. Anterior, middle, and posterior ethmoidal cells [Small mucous membrane-lined air spaces in the living = paranasal sinuses; See the hemiskull]

Parietal Bone (Paired)

1. Superior and inferior temporal lines 2. Parietal foramen (inconstant = for an emissary vein)

Types of Lungual Papillae

1. Vallate: Large, flat-topped. Anterior to the terminal sulcus. Surrounded by trenches whose walls are covered by taste buds. Serous glands of the tongue also open into these trenches. 2. Foliate: Small lateral folds of mucosa. Poorly developed in humans. 3. Filiform: Long and numerous. Sensitive to touch. 4. Fungiform: Mushroom-shaped scattered about. *All of the papillae have tastebuds except for the the filiform*

PPF: Communications With Other Regions of the Head *Posterior*

1.) *Foramen rotundum* opens high on the posterior wall, connecting to the middle cranial fossa; 2.) *Pterygoid Canal* opens a bit lower, connecting to the carotid cana 3.) Posteromedially, a small *Palatovaginal (Pharyngeal) Canal* communicates with the nasopharynx

PPF: Communications With Other Regions of the Head *Inferior*

1.) *Greater Palatine Canal* communicates with the palate. It bifurcates below, opening onto the hard palate via 2.) the *Greater and Lesser Palatine Foramina*

Superficial Cutaneous sensory branches of the cervical plexus: C1-4

1.) *Lesser occipital (C2)*: neck and SCALP posterosuperior to the auricle 2.) *Great auricular (C2,3)*: ascends vertically across SCM, usually posterior to the EJV, to serve the skin of the parotid gland, posterior auricle, and angle of the mandible to the mastoid process 3.) *Transverse cervical (C2,3)*: anterior triangle (passes anterior to SCM, but deep to the EJV and platysma) 4.) *Supraclaviculars (C3,4)*: neck and shoulder (emerge as a common trunk under the SCM)

Each Pharyngeal Arch is composed of...

1.) *Mesenchyme* 2.) *Neural crest* 3.) A *cartilage bar* (made from neural crest) 4.) An outer layer of *ectoderm* 5.) An inner layer of *endoderm* 6.) A *cranial nerve* (or cranial nerve branch) 7.) An *artery* (derived from the aortic arches)

Root of the Neck: Skeletal Framework

1.) *Superior thoracic aperture* - allows continuity between the neck and superior mediastinum. Be familiar with its boundaries 2.) *Cervical vertebrae* - Know their gross structure, their bodies and transverse processes will prove important 3.) *Clavicle*

Parts of the Membranous Labyrinth

1.) 3 Semicircular Ducts and Ampullae 2.) Utricle and Saccule 3.) Vestibular Ganglion 4.) Cochlear Duct

V3 Mandibular Nerve Pathway

1.) Arises from the trigeminal ganglion and together with the motor root of V passes through foramen ovale to the infratemporal fossa 2.) Just inferior to foramen ovale V3 is joined by the motor root (V3 = mixed nerve) 3.) Within the infratemporal fossa V3 divides into many large nerves such as the auriculotemporal, lingual and inferior alveolar nerves

Cranial Nerves vs Spinal Nerves: Differences

1.) CN Not formed by union of dorsal and ventral roots - Some CN's are mixed, some are not 2.) CN attach to brain, not spinal cord (except XI) 3.) CN exit the Cranial Cavity through various openings (Canals, Meatuses, Fissures, Foramina) 4.) CN do not form plexuses

CN VII Facial Nerve Course Details

1.) CN VII traverses the temporal bone through the facial canal 2.) At the first bend of the facial canal CN VII widens to form the *geniculate ganglion* 3.) From here the facial nerve sweeps inferiorly behind the middle ear and emerges from the skull at the *stylomastoid foramen* 4.)Then enters the *parotid gland* (but does Not innervate) - within the parotid gland the facial nerve gives rise to its *terminal branches*

Cranial Dural Partitions

1.) Falx Cerebri 2.) Falx Cerebelli 3.) Tentorium Cerebelli 3.) Diaphagma Sellae

The Trail of Tears

1.) From Lacrimal Duct tears pass 2.) Inferomedially across the eye 3.) Pass into the puncta 4.) Enter the lacrimal caruncle 5.) Enter Lacrimal sac 6.) Pass through the nasolacrimal duct - Eyelids act as a squeegee wiping tears from the upper lateral corner to the lower medial corner

Thyroid Pathologies and Congenital Defects Include

1.) Goiter 2.) Thyroglossal Duct Cysts 3.) Thyroglossal Sinuses 4.) Thyroid Tumors 5.) Ectopic Thyroid Tissue

There are three branches of the facial nerve given off within the facial canal:

1.) Greater Petrosal Nerve 2.) Nerve to Stapedius 3.) Chorda Tympani Nerve

Opthalmic Artery Branches in the Orbit

1.) Lacrimal Artery 2.) Ciliary Arteries The main stem of the ophthalmic artery passes anteromedially. As it takes this course it gives off several other branches: 3.) Supraorbital Artery 4.) Anterior and Posterior Ethmoidal Arteries 5.) Palpebral Artery 6.) Dorsal Nasal Artery 7.) Supratrochelar Artery 8.) Central Artery of the Retina

External Features of the Eye

1.) Lacrimal Caruncle 2.) Plica Semilunaris 3.) Lacrimal Papilla 4.) Conjunctiva 5.) Iris 6.) Cornea 7.) Conjunctival Sac 8.) Tarsal Plate

Opthalmic Nerve (CN V1) Branches

1.) Lacrimal Nerve 2.) Frontal Nerve 3.) Nasociliary Nerve and Branches

Greater Petrosal Nerve

1.) Leaves CN VII at the *genu* 2.) Passes through the petrous temporal bone and then enters the floor of the middle cranial fossa 3.) Here it dives down through the foramen lacerum, passes through the pterygoid canal, and ultimately enters the Pterygopalatine (PP) Fossa Carries preganglionic parasympathetic fibers of VII to the pterygopalatine ganglion in the PP fossa. These fibers *supply the lacrimal gland and mucous glands in the nasal cavities and palate*

Facial Nerve - Course through Temporal Bone

1.) Leaves cranial cavity and enters the Petrous part of the temporal bone through the internal acoustic meatus along with the vestibulocochlear nerve (CN VIII) - At the lateral end of the meatus, the facial nerve enters the facial canal, where it is contained until it leaves the skull via the stylomastoid foramen 2.) In the facial canal, it first passes between the bony cochlea and bony vestibule, which are both parts of the internal ear 3.) Lateral to the cochlea, facial canal turns posteriorly, producing a sharp bend in the nerve (the *genu* of the facial nerve), which is also the location of the sensory ganglion of the facial nerve (geniculate ganglion) 4.) Distal to the genu, the facial nerve passes posteriorly in the facial canal midway between the tympanic cavity and the bony cochlea. As it does so, the facial canal produces the bony prominence of the facial canal on the upper medial wall of the tympanic cavity 5.) Posterior to the tympanic cavity, the facial canal bends inferiorly and descends between the tympanic cavity and mastoid air cells to the stylomastoid foramen

Chorda Tympani Nerve

1.) Leaves the facial nerve at the distal end of the facial canal and passes superiorly into the substance of the temporal bone via a bony canal 2.) Enters the tympanic cavity (middle ear cavity) 3.) Crosses the medial surface of the eardrum (tympanic membrane) 4.) Then passes through another bony canal to enter the infratemporal fossa 5.) Here chorda tympani joins the lingual nerve of V3

Cranial Nerves vs Spinal Nerves: Similarities

1.) Like Spinal Nerves, some CN *associated with Sensory Ganglia* 2.) Like Spinal Nerves, some CN *associated with Autonomic Ganglia* 3.) Like Spinal Nerves, some CN *carry Postganglionic sympathetic fibers to smooth muscle and glands (in the head & neck)*

Just inferior to/outside of the stylomastoid foramen, CN VII gives off:

1.) Motor branches to the stylohyoid and posterior belly of the digastric muscle. 2.) The posterior auricular nerve - to the auricular muscles (wiggle the ears) and the occipital belly of the occipitofrontalis muscle (moves the scalp).

Nerves of the Eye/Orbit

1.) Oculomotor Nerve (CN III) 2.) Ciliary Ganglion 3.) Trochlear Nerve (CN IV) 4.) Abducens Nerve (CN VI) 5.) Opthalmic Nerve (CN V1) and Branches

CN I - Olfactory Nerve Pathways

1.) Olfactory Bulb synapses with Olfactory Nerves above Cribiform Plate of the Nasal Cavity 2.) *Olfactory Tract* = Axons 3.) Synapses on Olfactory Cortex of Cerebrum

Course of the Facial Artery

1.) On its way to the face from the neck, the facial artery "grooves" the submandibular gland in the upper neck, and then crosses the mandible, where its pulsations are palpable and it can be compressed to alleviate bleeding on the face. 2.) From here, the facial artery heads across the face in an oblique course lateral to the nose, terminating at the medial corner of the eye near the root of the nose. 3.) On the face, the facial artery weaves about through the muscles of facial expression, usually passing deep to them.

Cartilages of the Nose

1.) Paired Greater Alar Cartilages 2.) Mobile part of the Nasal Septum 3.) Septal Cartilage with 2 Lateral Processes 3.) Several Lesser Alar Cartilages

Mesenchyme Within Pharyngeal Arches: 4 Sources

1.) Paraxial mesoderm (un-segmented = not somites ) 2.) Neural crest 3.) Lateral mesoderm 4.) Ectodermal placodes

Sensory Branches of V2 via Pterygopalatine Ganglion

1.) Pharyngeal 2.) Lesser Palatine 3.) Greater Palatine 4.) Nasopalatine 5.) Posterior Inferior Nasal (PIN) 6.) Posterior Superior Nasal (PSN) "Pharaohs Lost Great Noses PINned on SphyNxes"

Branches of the Pterygopalatine Ganglion (Branches of V2)

1.) Pharyngeal n. - to nasopharynx 2.) Nasopalatine n - to nasal septum and hard palate 3.) Posterior superior lateral nasal nn. - to posterior superior lateral nasal wall. 4.) Greater palatine n. - to hard palate 5.) Posterior inferior lateral nasal nn - to lateral nasal wall 6.) Lesser palatine n - to soft palate

Maxillary Nerve (V2) Branches in the PPF

1.) Posterior Superior Alveolar Nerves 2.) Zygomatic Nerve 3.) Ganglionic Branches Sensory Branches of V2 [pass through the pterygopalatine ganglion (without synapsing) and thus appear to be attached to the ganglion]: 4.) Pharyngeal Nerve 5.) Greater and Lesser Palantine Nerves 6.) Nasopalantine Nerve 7.) Posterior Superior Lateral Nasal Nerves 8.) Posterior Inferior Lateral Nasal Nerves

Branches of V2 within the PPF

1.) Posterior superior alveolar nn. 2.) Zygomatic nerve 3.) Ganglionic branches "PSA - Zebra Gangs!"

Fibroelastic Membranes

1.) Quadrangular Membrane 2.) Aryepiglottic Ligament 3.) Vestibular Ligament 4.) Conus Elasticus - Vocal Ligament

Root of Neck: Muscles

1.) Scalenus - Scalenus Anterior - Scalenus Medius - Scalenus Posterior 2.) Prevertebral Muscles

Functions of Thyroid Gland

1.) Secretes *Thyroid Hormones* - Thyroxine (T4) & triiodothyronine (T3) - Maintains metabolic rate 2.) Secretes *Calcitonin* - From C cells - Reduces blood calcium levels

Several nerves "hitch-a-ride" on the hypoglossal

1.) Several branches of the cervical plexus ride along to reach muscles of the neck (NOT hypoglossal nerve fibers - but fibers derived from the anterior rami of cervical spinal nerves) 2.) Superior root of the *ansa cervicalis* joins CN XII 3.) Other C-1 fibers

Root of Neck Blood and Lymph Vessels

1.) Subclavian Arteries and 4 branches a.) Vertebral Artery b.) Thyrocervical Trunk - Suprascapular a - Transverse Cervical a - Inferior Thyroid a c.) Internal Thoracic Artery d.) Costocervical Trunk - Highest Intercostal a - Deep Cervical a 2.) Subclavian Vein 3.) Thoracic Duct 4.) Right Lymph Duct

Innervation of the Lacrimal Gland - Pathway (Supposedly we need to know this...)

1.) Superior salivatory nucleus (pons) 2.) Pre-ganglionic PS fibers are in the Facial nerve 3.) [Internal acoustic meatus] 4.) [Facial canal] 5.) Greater petrosal nerve of VII 6.) [Leave petrous temporal bone via canaliculus] 7.) [Middle cranial fossa] 8.) [Foramen lacerum] 9.) [Pterygoid canal in sphenoid bone] 10.) Joins deep petrosal nerve (sympathetics) to form Nerve of the Pterygoid Canal 11.) [Pterygopalatine fossa] 12.) Pre-G fibers synapse on postganglionic PS fibers in the Pterygopalatine ganglion 12.) Post-G fibers join the Zygomatic nerve of V2 13.) [Enters orbit via inferior orbital fissure] 14.) Zygomaticotemporal nerve of V2 15.) Joins Lacrimal nerve of V1 16.) Lacrimal gland at last!!

Foramen of the Orbit

1.) Supraorbital Notch/Foramen 2.) Infraorbital Groove and Canal 3.) Inferior Orbital Fissure 4.) Superior Orbital Fissure 5.) Optical Foramen 6.) Opening for Anterior Ethmoidal Nerve 7.) Opening for Posterior Ethmoidal Nerve

Chorda Tympani Nerve Carries

1.) Taste fibers from the anterior two-thirds of the tongue. Cell bodies of these neurons are in the geniculate ganglion. 2.) Preganglionic parasympathetic fibers - these leave chorda tympani to "hitch-a-ride" on the lingual nerve to the submandibular ganglion where they synapse. Postganglionic fibers supply the submandibular and sublingual salivary glands

Cervical Chain Ganglia Constants!!!! KNOW THIS

1.) They all have *Gray Rami Communicantes* connected to cervical spinal nerves (several spinal nerves may receive gray rami from one ganglion). 2.)They all give off tiny *Cervical Cardiac Nerves*, which pass through the superior thoracic aperture to the cardiac autonomic nerve plexus.

Contents of the PPF

1.) Third part of maxillary artery 2.) Venous tributaries of pterygoid plexus 3.) Maxillary nerve (V2) and branches 4.) Pterygopalatine ganglion "Max the 3rd offers a Tribute of 2 Trees to the Pterodactyl Gang" (2-Trees rhymes with 2-"vees" = V2, trees have branches)

V2 Maxillary Nerve Pathway

1.) V2 is attached to the lateral wall of the cavernous sinus 2.) Passes through foramen rotundum to enter the pterygopalatine fossa. 3.) Within the pterygopalatine fossa many branches of V2 are given off, most notably the zygomatic and infra-orbital nerve 4.) Both zygomatic and infra-orbital nerves enter the orbit from the pterygopalatine fossa through the inferior orbital fissure

Terminal Lymph Drainage from entire Head and Neck Region

1.) Via *deep cervical nodes*, embedded in the CT of the carotid sheath and closely adherent to the Internal Jugular Vein 2.) Lymph from the Deep Cervical Nodes enters the *Left & Right Jugular Lymph Trunks* 3.) These may join the *Subclavian or Internal Jugular Veins* independently, OR they may join the *Right Lymph Duct* on the right side, and the *Thoracic Duct* on the left side

CN V Trigeminal Nerve Pathway

1.) the 2 roots pass together into the middle cranial fossa just above the petrous portion of the temporal bone 2.) Here the sensory root expands to form the trigeminal ganglion 3.) Distal to the ganglion the trigeminal nerve divides into its 3 branches 4.) The motor root of V continues inferior to the ganglion and joins the mandibular nerve = therefore only the mandibular branch of V contains motor fibers

Cavernous Sinuses

2 Sinuses located on either side of the sella turcica, posterior to the orbits - Interconnected cavities formed by connective tissue trabeculae that crisscross the sinuses, making blood flow sluggish - Connects to superficial veins via *ophthalmic veins*

Epicranial aponeurosis

2 flat skeletal muscles attached to its anterior and posterior ends move the SCALP forward and backward

Thyroid Cartilage Laminae

2 fused in the midline; form the *laryngeal prominence* - Attachment of inferior constrictor muscles

Pharyngeal Muscles Consist of...

2 layers - Outer circular - Inner longitudinal

Dura Mater

2 layers, periosteal (endosteal) and meningeal. - Periosteal layer is the periosteum of the skull bones

First Pharyngeal Arch

2 parts: the *Maxillary process* and the *Mandibular process* These are involved in the development of the face

Purely Motor Cranial Nerves

3 = Oculomotor 4 = Trochlear 6 = Abducens 11 = Spinal Accessory 12 = Hypoglossal Functional components: Skeletal motor fibers

Pterygopalatine ganglion and V2 Blocks: Approaches

3 anatomic approaches reported as a means of blocking PPG 1.) Lateral (sub-zygomatic arch) approach 2.) Intra-oral approach (through the greater palatine foramen) Both Rarely used for treating headaches and facial neuralgias 3.) Intra-Nasal: Preferred approach - An applicator soaked with anesthetic solution is placed posterior to the middle nasal concha for ~20-30 minutes, allowing the anesthetic to diffuse through the nasal mucosa into the pterygopalatine fossa

Scalenus Muscles

3 in number, lie deep to the sternocleidomastoid, but can be seen in the posterior triangle. - All 3 arise from the transverse processes of cervical vertebrae - Flexors of the neck, but can also act as accessory respiratory muscles when they are fixed above

Components of the Bony Labyrinth

3 interconnected *Semicircular Canals* (anterior, posterior, and lateral), each oriented at right angles to one another *Vestibule*: a spherical cavity with the oval window in its lateral wall; Communicates with the semicircular canals and the cochlea *Cochlea*: spiral canal shaped like a snail's shell. It makes two and one-half turns around a central bony core called the modiolus. The round window is located in the lateral wall of the base (first turn) of the cochlea

PS Ganglia Associated with Cranial Nerves

3,7,9,10 Oculomotor (III) = Ciliary Ganglion Facial (VII) = Pterygopalatine Ganglion Facial (VII) = Submandibular Ganglion Glossopharyngeal (IX) = Otic Ganglion Vagus (X) = Intramural Ganglia (Thoracic and Abdominal Cavities) "a Pair-o' Silly Pterodactyls Soar Over Intramural Games"

CN 3 Skeletal Motor Component

4 extraocular muscles + levator palpebrae superioris muscle Motor nucleus in *midbrain* 1.) CN III emerges from the *anterior surface of the midbrain near its junction with the pons* 2.) Passes anteriorly between the posterior cerebral and superior cerebellar arteries 3.) Pierces the dura mater and passes through the cavernous sinus (bathed by venous blood) 4.) As it leaves the cavernous sinus it divides into a *superior and an inferior division* 5.) Divisions then pass through the superior orbital fissure and enter the orbit. - Superior division supplies: levator palpebrae superioris and superior rectus muscles - Inferior division supplies: medial rectus, inferior rectus, and inferior oblique muscles

Pharyngeal Gaps

4 gaps

Mixed Sensory and Motor Cranial Nerves

5 = Trigeminal 7 = Facial 9 = Glossopharyngeal 10 = Vagus Carry motor and sensory fibers Carry somatic and visceral fibers

Sensory Ganglia of Cranial Nerves

5,7,8,9,10 *Trigeminal (V) = Trigeminal Ganglion Facial (VII) = Geniculate Ganglion Vestibulocochlear (VIII) = Cochlear Ganglion, Vestibular Ganglion Glossopharyngeal (IX) = Superior and inferior ganglia of IX Vagus (X) = Superior and inferior ganglia of X* (Cap't Hook on a date with a Shark named "Genni", their Snowman waiter hands them two Balloons and two Plate and Spoons)

Prominence of the Facial Canal

A bony ridge located on the upper medial wall near the roof, formed by the *Facial Nerve* as it passes posteriorly after leaving the geniculate ganglion

Nasal Branches of the Infraorbital Nerve

A branch of *CN V2* Supply the area of the vestibule

LeFort Type III

A horizontal fracture through the greater wings of the sphenoid bones, frontozygomatic sutures, superior orbital fissures, and ethmoid bone. This essentially separatesthe facial skeleton from the cranial vault. Fracture of the ethmoid bone can cause leakage of CSF into the nasal cavity (CSF rhinorrhea).

CN VII Facial Nerve Course Basic

A mixed nerve with a complicated course *within the temporal bone* 1.) Together with cranial nerve VIII, the two parts of the nerve pass briefly through the posterior cranial fossa then enter the internal acoustic meatus 2.) At the distal end of the meatus the two parts of VII fuse and the facial nerve enters the facial canal in the temporal bone

Limen Nasi

A ridge that indicates the junction within the nasal cavity between the vestibule and the nasal cavity proper - Also a transition between skin and the mucous membrane. The skin here is highly sensitive whereas the mucous membrane is not as sensitive

Vertebral Ganglion

A second ganglion, the vertebral ganglion, May be present anterior to the vertebral artery, near its origin from the subclavian. If present, it gives off the *Ansa Subclavia*, instead of the middle cervical ganglion - Middle cervical and vertebral ganglia may be fused, forming an extra large middle ganglion.

Genu of the Facial Nerve

A sharp bend in the nerve produced by the facial canal turning posteriorly lateral to the cochlea - this is also the location of the *sensory ganglion of the facial nerve (geniculate ganglion)*

Thyrocervical Trunk

A short stump, typically giving off three branches: - Suprascapular artery - Inferior thyroid artery - Transverse cervical artery "SIT"

Pterygopalatine Fossa (PPF)

A small, bilateral bony space, deeply placed in the head - Shaped like an inverted cone - No larger in size than your thumbnail

Myringotomy

A surgical procedure called a myringotomy creates a tiny opening in the tympanic membrane to drain fluid or pus from the tympanic cavity due to otitis media. The membrane heals nicely. In some children, myringotomy tubes are placed in the tympanic membrane to ventilate the tympanic cavity.

Branchial Fistula

A tract or small canal that has two openings: one external and one internal. - External opening is usually along the anterior border of the sternocleidomastoid - Internal opening is near the tonsillar fossa

CN VI

Abducens Nerve Skeletal motor: innervates the *lateral rectus muscle* (extraocular eye muscle). - abduction of the eyeball

Posterior Cricoartrenoid Muscle

Abducts the Vocal Folds

Mallear Prominence and Folds

Above the umbo, another part of Malleus attaches to tympanic membrane, producing *Mallear Prominence* - attachment produces a crease in the tympanic membrane (*anterior and posterior mallear folds*) on the internal surface

Posterior Triangle Nerves

Accessory Nerve Roots of Brachial Plexus Cervical Plexus - Phrenic Nerve

Lateral Cricoarytenoid and Transverse Oblique Arytenoid Muscle

Adduct the Vocal Folds

Angular Artery

After giving off the lateral nasal artery, the facial artery parallels the nose. Here it is known as the angular artery. It terminates at the medial corner of the eyelids by anastomosing with the dorsal nasal artery (a terminal branch of the ophthalmic artery).

CN IX Glossopharyngeal Nerve Course

After leaving the cranial cavity through the anterior part of the jugular foramen, CN IX descends between the internal jugular vein and the internal carotid artery. It passes deep to the styloid process between the internal and external carotid arteries and curves anteriorly around the stylopharyngeus muscle. From here it enters the pharynx by passing through the gap between the superior and middle constrictors of the pharynx. It terminates near the base of the tongue.

Jugular Foramen

All dural sinuses drain, where the Internal Jugular Vein (IJV) begins

Filiform Papillae

All of the papillae have tastebuds except for the the filiform

Carotid Sheath

All three previous layers of deep fascia fuse to form the carotid sheath - Surrounds the major neurovascular bundle of the neck, so it is a potential space that is continuous from cranial cavity to mediastinum where infections and extravasated blood can spread *Contents*: CCA, ICA, IJV, X, deep cervical lymph nodes, sympathetic periarterial plexuses, and nerve branches to the carotid body & sinus

Intrinsic Laryngeal Muscles

Alter length or tension of the vocal ligaments, or change the size and shape of the rima glottidis

Lateral View of Paranasal Sinuses

Alternate view

Cervical Sinus

An embryonic potential space that normally disappears= the fused 2nd, 3rd and 4th pharyngeal clefts

CN XII Hypoglossal and Occipital Artery

An important landmark in the dissecting lab is the occipital artery, a branch of the external carotid. CN XII loops forward around the occipital artery, and then passes deep to the central tendon of the digastric muscle and the mylohyoid muscle to enter the tongue.

Venous Drainage of the Face

Angular Vein - Supraorbital Vein - Supratrochlear Vein Facial Vein Ophthalmic Veins (Superior and Inferior) Deep Facial Vein Pterygoid Plexus - Sphenoid Emissary Vein

Omohyoid (Innervation)

Ansa cervicalis (motor part of cervical plexus): C1-3 - Two bellies (superior and inferior) with the tendon attached to the clavicle

Sternothyroid (Innervation)

Ansa cervicalis (motor part of cervical plexus): C2,3 - Lies deep to the sternohyoid and attaches to the oblique line of the thyroid cartilage

Sensory Innervation of the Tongue - Anterior 2/3 vs Posterior 1/3

Anterior 2/3 - innervated by the lingual nerve (CN V - general sensation) and the chorda tympani (taste CN VII). Posterior 1/3 - innervated by glossopharyngeal (CN IX) for both general sensation and taste. There is also a tiny patch innervated by the internal laryngeal branch of CN X

Cranial Fossa

Anterior Cranial Fossa (ACF) Middle Cranial Fossa (MCF) Posterior Cranial Fossa (PCF)

Innervation of Anterior and Middle Ethmoid Air Cells

Anterior Ethmoid Nerve

Blood Supply to the Nasal Septum

Anterior and Posterior Ethmoidal Arteries Septal branches of Sphenopalatine Septal branches of Superior Labial Greater Palatine via the Incisive Foramina - Most of these vessels anastomose inferiorly forming a network of vessels called Kiesselbach's Plexus

Submandibular Sub-Triangle Borders

Anterior and posterior bellies of the digastric and the mandible Floor is formed by the mylohyoid, hyoglossus and middle pharyngeal constrictor muscles

Sphenoid Lesser Wing (Paired)

Anterior clinoid process

Neck Boundaries

Anterior neck ("neck proper" or cervix): extends from the inferior border of the mandible to the clavicles and sternum Posterior neck (nucha or "nape"): extends from the occipital bone and mastoid processes, to C7, then to the trapezius muscles. - The posterior bony skeleton is C1-7, bounded inferiorly by the clavicle and manubrium

Facial Skeleton (Viscerocranium)

Anterior portion of the skull; consists of seven bones. This is the skull MINUS the bones of the neurocranium!

Subclavian Veins

Anterior to the anterior scalene and phrenic nerve and drains the upper extremity - Joins IJV to form brachiocephalic vein

Tonsilar Lymphatics Drain...

Anteriorly to the lymph nodes near the angle of the mandible; primarily to the *Jugulodigastric node (or tonsillar node)* - This is why a pharyngitis/tonsillitis will manifest with swollen lymph nodes in this area

Hyoid

Arches 2 and 3 2 = Upper Body, Lower Horns of Hyoid 3 = Upper Horns, Lower Body of Hyoid

2nd, 3rd, and 4th Pharyngeal Clefts

Are overgrown by the second pharyngeal arch when the smooth neck forms. Subsequently, they fuse to form the cervical sinus, a potential space that normally obliterates later in development

Spinal Nerves Review

Arise from spinal cord, Mixed nerves formed by union of Ventral and Dorsal roots. Exit via Intervertebral Foramina; once outside the vertebral column they split into Ventral and Dorsal Rami. Ventral Rami of Cervical, Upper Thoracic, and Lumbosacral regions form Plexuses. Dorsal Rami do not form plexuses.

CN XII Hypoglossal Course

Arises as multiple rootlets from the hypoglossal nucleus in the medulla, between the pyramid and the olive 1.) Rootlets unite in the posterior cranial fossa 2.) Exits the cranial cavity through the *Hypoglossal Canal* 3.) Descends between the internal carotid artery and internal jugular vein, and then passes anterior to the vagus and deep to the posterior belly of digastric

Tympanic Nerve (Jacobsen's Nerve)

Arises from Glossopharyngeal (IX) in jugular foramen and enters Tympanic Cavity through its floor to join the tympanic plexus *Sensory fibers*: innervate the mucosa of the tympanic cavity and preganglionic *Secretomotor fibers*: enter the lesser petrosal nerve

Nerve to the Stapedius

Arises from the facial nerve as it descends in the facial canal and supplies the stapedius muscle while it is within the pyramid

CN IX Tympanic Nerve (Jacobsen's Nerve)

Arises from the inferior ganglion of IX and passes superiorly into the tympanic cavity through a tympanic canaliculus. The tympanic nerve carries *sensory fibers from mucosa in the tympanic cavity and preganglionic parasympathetic fibers that will innervate the parotid*. In the tympanic cavity the tympanic nerve contributes fibers to the tympanic plexus (more on this when we discuss the ear). Some of the fibers of the tympanic nerve will reunite distal to the tympanic plexus to form the lesser petrosal nerve = these contain preganglionic parasympathetic fibers. The lesser petrosal nerve leaves the tympanic cavity, enters the middle cranial fossa, then drops down into the infratemporal fossa through foramen ovale. Here preganglionic fibers synapse on neurons in the otic ganglion

Arteries of the Tongue

Arteries: derived from the *Lingual artery, a branch of the external carotid.* They then branch into the *Dorsal and Deep lingual arteries*

Arytenoid Cartilages and Cricoid

Articulate with the cricoid cartilage - Most muscles of phonation attach to the cricoid cartilage

CNXII Hypoglossal Nerve Arises

As many rootlets from the hypoglossal nucleus in the medulla - between the pyramid and the olive

Vertebral Artery

Ascends through the transverse foramina of cervical vertebrae (but misses the 7th) Enters foramen magnum, and helps supply blood to the brain

Middle Cervical Ganglion

At *C6, opposite the larynx* Connected to the cervicothoracic ganglion by two bands of nerve fibers, which represent a splitting of the sympathetic trunk around the subclavian artery - One band goes behind - the other band, the *ansa subclavia* loops into front of the artery

Infrahyoid muscles

Attach hyoid bone and larynx to sternum and scapula. Antagonists of suprahyoid muscles; depress the hyoid and larynx after having been elevated during swallowing. Infrahyoid and suprahyoid muscles work together to stabilize hyoid so it can form a solid base for the muscles that move tongue. (all ansa cervicalis except Thyrohyoid = C1) - Sternohyoid - Sternothyroid - Thyrohyoid - Omohyoid

Suprahyoid muscles

Attach the hyoid bone to the mandible and temporal bones. They constitute the floor of the mouth, are involved in elevating the hyoid bone during the first stages of swallowing, and they assist in opening the mouth. - Geniohyoid - Mylohyoid - Digastric - Stylohyoid "Genny, My (hair) Dye Stylist is SUPER!"

Clivus

Attaches occipital bone to sphenoid bone - within the posterior cranial fossa between the dorsum sellae and the foramen magnum upper part lies just posterior to the dorsum sellae and is formed by the body of the sphenoid bone lower part extends to the foramen magunum and is formed by the basilar part of the occipital bone

Conus Elasticus

Attaches to the superior border of the cricoid cartilage

Median Cricothyroid Ligament

Attaches to thyroid cartilage - Where larynx is closest to the skin and is most accessible; can be felt as a soft spot inferior to the thyroid cartilage

Thyro-Epiglottic Ligament

Attachment to the angle formed by the thyroid laminae of the tapered inferior end of the epiglottis

Innervation of the External Acoustic Meatus

Auriculotemporal Nerve and the Auricular Branch of the Vagus

Beyond the 1st rib the Subclavian Artery is known as...

Axially Artery

Medial vs Lateral Retina Axons

Axons from medial retina cross-over at optic chiasma- axons from lateral retina do not

CN II - Optic Nerve Pathways

Axons of retinal ganglion cells (neurons) project from the eye to the thalamus (diencephalon) - these axons make up the optic "nerves" and optic tracts

Parotid Compression

Because of its location, the parotid is compressed when the mouth is opened and pain may be elicited when the gland is swollen (e.g., due to mumps or a blocked duct).

Respiratory Layer - Trachea

Begins at *C6* and passes downward into the thoracic cavity. Anterior aspect of tracheal cartilages 2-4 usually covered by the isthmus of the thyroid gland Below that, the trachea in the neck is usually overlaid by *inferior thyroid veins*, which pass inferiorly to the left brachiocephalic vein --> These are an impediment to performing an emergency tracheotomy in the field

Pars Tensa

Below the mallear folds, tympanic membrane possesses the central core of connective tissue (collagen and elastic fibers), making the membrane here rather rigid, like the head on a snare drum

Parasympathetic Fibers Associated with V3 - *Sublnigual Ganglion Postganglionic*

Below the tongue, the lingual nerve of V3 is joined to the Submandibular Ganglion (parasympathetic ganglion) *Postganglionic parasympathetic fibers "hitch-a-ride" on the lingual nerve in order to innervate the submandibular and sublingual salivary glands as well as minor salivary glands in the mucosa of the oral cavity*

Parasympathetic Fibers Associated with V3 - *Sublnigual Ganglion Preganglionic*

Below the tongue, the lingual nerve of V3 is joined to the Submandibular Ganglion (parasympathetic ganglion) *Preganglionic parasympathetic fibers derived from the facial nerve (VII) synapse here*

Respiratory Layer - Larynx

Between *C4 and C6*; its thyroid and cricoid cartilages can be palpated easily Continuous inferiorly with the trachea, which begins at C6, just below the cricoid cartilage

Subclavian Artery Part I

Between its origin and the medial border of the anterior scalene muscle

Between the Cervicothoracic and Superior Cervical Ganglia

Between the cervicothoracic and superior cervical ganglia the waters get murky: - one or two ganglia may be present. Usually there is a middle cervical ganglion

Subclavian Artery Part III

Between the lateral border of the anterior scalene and the first rib

Potential Spaces of the Neck

Between the layers of deep fascia in the neck, around the pharynx, and in the floor of the mouth. Infections may spread through these spaces and can sometimes spread into the thorax - Retropharyngeal Space - Pretracheal Space - Lateral Pharyngeal Spaces, Parapharyngeal Space - Submandibular Space

Palantine Tonsils

Between the palatoglossal folds lie the tonsillar fossae containing the palatine tonsils, masses of lymphoid tissue commonly referred to as "tonsils"

CN VIII - Vestibulocochlear Nerve Pathways: Vestibular Nerve

Bipolar neurons - Cell bodies in the vestibular ganglion situated in the internal acoustic meatus - Peripheral processes of the bipolar neurons penetrate the temporal bone to be distributed to receptors in the utricle, saccule and semicircular ducts - Central processes enter the brainstem and synapse on vestibular nuclei at the *Ponteomedullary Junction*

CN VIII - Vestibulocochlear Nerve Pathways: Cochlear Nerve

Bipolar neurons Cell bodies in the spiral ganglion lodged in the bony central core of the cochlea in the inner ear Peripheral processes are distributed to hair cells in the spiral organ (of Corti) in the cochlea Central processes enter the brainstem and synapse on cochlear nuclei in the medulla

Pterygopalatine ganglion and V2 Blocks

Blockage of the PPG with an anesthetic has been shown to be useful in management of migraines, other types of headaches, and various types of facial neuralgias that don't respond to conventional pharmacologic therapy

Emissary Veins

Blood flow: SCALP superficial veins --> emissary veins -> diplöic veins --> dural venous sinuses --> internal jugular vein

In the Facial Canal the Facial Nerve passes between which two structures?

Bony Choclea and Bony Vestibule (both part of inner ear)

Nasal Cavities - Floor and Roof

Bony floor formed by the Hard Palate Cribriform plate of the Ethmoid bone forms the roof

Piriform Aperture

Bony opening into the nasal cavity. The nasal and maxillary bones form the boundaries of the piriform aperture. Skin and hyaline cartilages surround this opening are connected by perichondrium and periosteum.

Submental Sub-Triangle

Borders: hyoid, mandible, and the right and left digastric anterior bellies. The floor is the 2 mylohyoid muscles, which form the median fibrous raphe Contents: submental lymph nodes and small veins that unite to form anterior jugular vein

Muscular Sub-Triangle

Borders: neck midline, superior belly of the omohyoid, and anterior border of the SCM. Its floor is formed by the sternohyoid and sternothyroid muscles Contents: pretracheal fascia covers infrahyoid muscles and neck viscera The floor muscles are often reflected for surgical access to the thyroid gland, larynx, and trachea

Root of Neck - Trachea and Esophagus

Both pass through the center of the superior thoracic aperture Trachea can be easily palpated here just above the suprasternal notch. In the groove between these organs are the recurrent laryngeal nerves

Scalp Arteries from *Internal* Carotid

Branches of *Ophthalmic * Artery - Supraorbital artery - Supratrochlear artery

Cutaneous Nerves

Branches of all three divisions of the trigeminal nerve supply the face V1: forehead, upper eyelid, and dorsum of nose V2: lower eyelid, infra-orbital region, temporal region, and sides of the nose V3: chin, lower lip, cheek, and temporal region

Paranasal Sinus Innervation

Branches of the *Trigeminal nerve* innervate mucous membranes that line the paranasal sinuses 1.) Frontal Sinus: Supraorbital Nerve, 2.) Anterior and Middle Ethmoid Air Cells: Anterior Ethmoid Nerve 3.) Posterior Ethmoid Air Cells and Sphenoid: Posterior Ethmoid Nerve 4.) Maxillary Air Sinus: Posterior, Middle, and Anterior Superior Alveolar

Cervical Cardiac Nerves

Branches off of the Cervical Ganglion that go to Cardiac Plexuses - Contain predominantly unmyelinated postsynaptic neurons and run deeply in the neck to the cardiac and pulmonary plexuses to reach target tissue

Promonotory

Bulge produced by the basal (first) turn of the cochlea Most prominent feature of the Medial Wall of the Middle Ear - On it's surface is the Tympanic Plexus of Nerves

Cleft Lip

By far the most common facial cleft. Caused by *failure of the maxillary prominences to fuse properly with the intermaxillary segment along the edge of the philtrum*. - Underdevelopment of mesenchyme, due to inadequate migration of neural crest or excessive cell death, is thought to be the reason - Degree of clefting is variable, from small notches in the border of the lip to complete separation of the lip and underlying bone

Geniohyoid (Innervation)

C1 by hitching a ride on XII

CN XII and C1 Spinal Nerve Motor Fibers

C1 spinal nerve motor fibers "hitch-a-ride" on CN XII to their destinations - CN XII courses "under" the tongue to supply tongue muscle - C1 fibers innervate: geniohyoid, thyrohyoid, sternohyoid, sternothyroind, omohyoid

Long Thoracic Nerve

C5-C7 roots, supplies the serratus anterior muscle.

Carotid Sub-Triangle Contents

CCA and branches (*Some Anatomists Like Freaking Out* Poor Medical Students) Superior root of ansa cervicalis Thyroid gland Larynx Deep cervical lymph nodes Inferior Jugular Vein CN X Branches of the cervical plexus - This triangle is important for surgical access to the ICA for angiography or endarterectomy External Carotied Artery Branches: Some Anatomists Like Freaking Out Poor Medical Students (Superior Thyroid, Ascending Pharyngeal, Lingual, Facial, Occipital, Posterior Auricular, Maxillay, Superficial Temporal) - All of these are in the Carotid Triangles except for the "Poor Medical Students" who get left out

Cranial Nerves and the Cranial Cavity

CN I: Cribiform Plate CN II: Optic Channel CN III, IV, VI and V1: Superior Orbital Fissure CN V "Standing Room Only" (V1 = Superior Orbital Fissure, V2 = Foramen Rotundum, V3 = Foramen Ovale) CN VII, VIII: Internal Accoustic Meatus CN IX, X, XI: Jugular Foramen CN XII: Hypoglossal Foramen

Innervation of the Parotid

CN IX

Sensory Innervation of Pharynx

CN IX - all 3 parts of the pharynx, plus: CN V2 - anterior and superior nasopharynx

Sternocleidomastoid muscle (SCM) Innervation

CN XI (some branches of the cervical plexus may be afferent in function)

CN XI "Plexus"

CN XI communicates with branches of C2, C3, and C4 spinal nerves, forming sort of a plexus with them. Proprioception from SCM and trapezius are thought to center the CNS through these spinal nerves - and not through CN XI itself.

Parasympathetic Ganglion Mnemonic

COPS (Ciliary, Optic, Pterygopalatine, Submandibular) or... Silly Old People stay Mouldy Silly Ciliary Old Optic People Pterygopalatine Stay Mouldy SubMandibular

Facial Nerve Dysfunction (e.g. Bells Palsy)

Can paralyze the stapedius, leaving the patient with *hypersensitivity to sound* (hyperacusis) since the stapedius can no longer carry out its function in dampening the vibrations of the stapes

Serious Complications of Otitis Media

Can produce infections in the mastoid antrum and mastoid air cells (mastoiditis) or worse, infections could spread through the thin bony roof of the tympanic cavity/mastoid antrum to the meninges in the cranial cavity (meningitis)

Carotid Plexuses

Carotid nerves pass onto the internal and external carotid arteries, forming internal and external carotid plexuses

Abducens Nerve Palsy (CN VI)

Causes an inward deviation of the eye and paresis of abduction Numerous causes: infarction, aneurysm, tumor, trauma, leptomeningitis, multiple sclerosis, often times is idiopathic

Oculomotor Nerve (CN III) Palsy

Causes ptosis, and inability to turn the eye inward, downward or upward May involve the pupil (here: *Mydriasis* as the sympathetic tone is intact) - Causes are numerous (same as with CN VI palsies)

Lateral Rectus

Causes the eye to turn away from the midline so the gaze is directly laterally --> Produces *Abduction of the eyeball*

Where are the Cell Bodies of Cranial Nerves that carry Postganglionic Sympathetic fibers to smooth muscle and glands (in the head & neck)?

Cell bodies of neurons are in *Superior Cervical Ganglion* - The pathway to target organs is different compared to that for spinal nerves

CN VII Facial Nerve: Parasympathetic Component

Cell bodies of preganglionic neurons are in the *superior salivatory nucleus in the pons* Preganglionic axons are in the *nervus intermedius* - These fibers pass into two important branches of the facial nerve: the greater petrosal and chorda tympani nerves - Preganglionic fibers in these nerves synapse on postganglionic neurons in the pterygopalatine and submandibular ganglia, respectively. Parasympathetic fibers in VII innervate the lacrimal gland (tear secretion), nasal glands (mucous secretion), the submandibular and sublingual salivary glands, and other mucous glands in the oral cavity

CN IX Glossopharyngeal Nerve Parasympathetic Component

Cell bodies of preganglionic neurons are in the inferior salivatory nucleus in the medulla. Preganglionic fibers are carried in the lesser petrosal nerve, a branch of IX. These nerve fibers synapse on neurons in the otic ganglion in the infratemporal fossa. Postganglionic fibers "hitch-a-ride" on the auriculotemporal nerve (of V3) to the parotid gland. CN IX thus innervates the parotid gland causing it to secrete saliva. No worries - we will draw out this pathway later.

Concha

Central deep depression. *Cavity of the concha* communicates with the opening of the external acoustic meatus *Cymba of the concha continues superiorly as a deep cavity between the anterior-most parts of the helix and antihelix

Middle Cranial Fossa (MCF)

Central portion of the cranial cavity - Sphenoid bone: greater wings and body - Temporal bone: petrous and squamous parts *Contents* - Temporal lobe of the cerebrum (between greater wing and petrous part) - Sella turcica (L=Turkish saddle): At the anterior boundary of the MCF *see next card* *Foramen*: Optic Canal, Superior Orbital Fissure, Foramen Rotundum. Foramen Ovale, Foramen Spinosum, Sphenoidal Emissary Foramen of Vesalis, Foramen Lacerum, Carotid Canal, Hiati for lesser and greater Petrosal Nerves - Internal Acoustic Meatus "Oh (Optic Canal) Standing (superior orbital fissure) Room (foramen rotundum) Only (foramen ovale) Sister (foramen spinosum) so (sphenoidal emissary foramen of vesalius) let's (foramen lacerum) check (carotid canal) Pete's (hiati for lesser and greater Petrosal nerves)"

Arterial Supply to Brain

Circle of Willis

Teeth Arrangement

Classified as incisors, canines, premolars and molars Arranged into superior (maxillar) and inferior (mandibular) dental arches - Each arch is divided into quadrants containing 8 teeth Total of 32 permanent and 20 deciduous (baby teeth) teeth

Peripheral nodes: Superficial group

Collect lymph from the Superficial fascia and skin of the neck These are *Anterior Jugular Nodes* and *External Jugular Nodes*, located along the veins of the same name Lymph from these nodes enters Deep Cervical Nodes

Peripheral nodes: Deep group

Collect lymph from tissues DEEP to the investing layer of deep fascia that does not drain directly to the deep cervical node - *Paratracheal nodes - Pretracheal nodes - Thyroid nodes - Tetropharyngeal nodes*

Auricle (List All Parts of it)

Collects sound waves 1.) Helix & Antihelix 2.) Scapha (Scaphoid fossa) 3.) Tragus & Antitragus 4.) Concha - Cavity - Cymba 5.) Lobule

What 2 Important Structures are located Lateral to the Trachea?

Common carotid arteries and lobes of the thyroid gland

Mastoid Antrum

Common cavity that communicates with a variable number of small mucosa-lined cavities called mastoid air cells. The Antrum and Air cells are within the *Mastoid Process* of the temporal bone.

Deviated Septum

Common disorder of the nasal cavity, caused by trauma or may be congenital and associated with genetic disorders Occurs when the cartilaginous nasal septum deviates to either side - Can be a cause of chronic congestion, sinus infections (due to impaired drainage) and snoring and sleep apnea Treatment is surgical (*Septoplasty*) where the cartilage is reshaped under anesthesia

Cricoid Cartilage

Complete cartilage (skinny front arch and wide posterior lamina)

Superficial Fascia of the Face

Composed of loose areolar CT and fat, providing a porous substrate for fluid or blood to accumulate

Pharyngeal Membrane Structure

Composed of two layers: - Ectoderm (external) - Endoderm (internal). Located where the pharyngeal clefts are juxtaposed with pharyngeal pouches

Thoracic Outlet Syndrome

Compression or irritation of the brachial plexus and/or subclavian artery can produce a set of symptoms, which may include pain, numbness, tingling, weakness, or coldness in the upper limb *Symptoms* may be caused by: 1.) Compression of the inter-scalene space 2.) Costoclavicular approximation = lessening of the space between the clavicle and first rib, due to trauma or postural problems 3.) An extra rib (cervical rib) or extra long transverse process of C7 4.) Compression by the tendon of pectoralis minor

Deep Facial Vein

Connects the facial vein to the pterygoid venous plexus in the infratemporal fossa - Passes through the buccal fat pad

Larynx

Connects the oropharynx with the trachea and spans the *C4-6 vertebrae* Consists of cartilages, ligaments, skeletal muscles, vocal folds, a mucosal lining, nerves, and arteries The "skeleton" of the larynx is actually composed of cartilage Most important function is to guard the airway, especially during swallowing

Tarsal Plate

Consists of dense fibrous connective tissue joined medially and laterally by *medial and lateral palpebral ligaments* Above and below are covered by the palpebral fibers of orbicularis oculi - Superior tarsal plate is also the attachment point for levator palpebrae superioris and the smooth muscle fibers (tarsal muscle or Mueller's muscle)

Branches of V2 that Connect with the Pterygopalatine Ganglia...

Contain 3 functional components: 1.) Sensory fibers with cell bodies in the Trigeminal ganglion 2.) Postganglionic sympathetic fibers with cell bodies located in the superior cervical ganglion 3.) Postganglionic parasympathetic fibers with cell bodies in the pterygopalatine ganglion

Vocalis Muscle

Contained in each vocal fold - Serves as the main inspiratory sphincter when tightly closed, and is an effective sphincter when it's completely closed - Attaches along the entire length of the vocal ligament - Individual parts contract and produce fine, localized adjustments of the vocal ligaments = tense some portions of the vocal ligament while simultaneously relax other parts

Nervus Intermedius

Contains 1.) Sensory fibers from a small region of skin of the external ear 2.) Parasympathetic secretomotor fibers for the lacrimal gland and salivary glands (submandibular and sublingual) 3.) Taste fibers from the anterior two-thirds of the tongue

Trigeminal Ganglion

Contains cell bodies of afferent neurons of CN V Enclosed within an outpocketing or sleeve of dura called the trigeminal cave (aka = Meckel's cave)

Internal Ear

Contains organs specialized for *Reception of sound and Detection of the position and movement of the head* - info needed for balance and equilibrium Mmade up of a series of cavities carved out of the *Petrous part of the temporal bone (bony labyrinth)* that contain a network of membrane-lined ducts and sacs *(membranous labyrinth)*

Ear

Contains the organs of hearing & balance Most of it is within the *Temporal Bone* Three portions: - External ear - Middle ear - Internal ear

Olfactory Area

Contains the peripheral processes of olfactory neurons - a sniff will get the air up into the olfactory area

Cochlear Duct

Contains the spiral organ (organ of Corti), where the special receptor cells for hearing are housed Occupies a central position within the bony cochlea Roof: Vestibular Membrane Floor: Basilar Membrane Because of its central location, the cochlear duct (containing *Endolymph*!!) subdivides the cavity of the cochlea into 2 *Perilymph-filled channels*: - Scala vestibuli above cochlear duct - Scala tympani below cochlear duct

Recurrent Laryngeal Nerve Damage

Could be affected during a thyroidectomy or parathyroidectomy by: 1.) Transection: *complete paralysis*, with the vocal folds staying halfway between abduction and adduction, and the person can't speak or cough; 2.) Trauma only: *partial paralysis*, adducted folds (posterior cricoarytenoid is most vulnerable), and he cannot breathe (*bilateral: disaster*; unilateral: partial compensation).

Root of Neck - Apex of Lung

Covered by *cervical pleura*, projects from the thorax above the level of first rib, into the root of the neck. Subclavian artery and vein groove the pleura just anterior to the apex. The cervical pleura is reinforced by a layer of connective tissue (analogous to endothoracic fascia) called the *Suprapleural Membrane* - Note that the lungs and pleura are vulnerable to injuries in the region of the *Supraclavicular fossa*!!

Inferior Surface of Tongue

Covered by a thin layer of mucous membrane *Frenulum* is a midline fold of mucous membrane that connects the tongue to the floor of the mouth. Lateral to it at its base is the *Sublingual caruncle* and the opening of the *Submandibular duct*

Cranial Meninges

Coverings of the CNS. In the cranial cavity covers the brain and brainstem. Cranial dura mater is firmly attached to the bones of the cranial vaults. *Functions*: protection; blood vessel scaffolding; formation of venous sinuses; and formation of the continuous sac called the subarachnoid space (located between the arachnoid mater and pia mater), for the flow of cerebrospinal fluid

Prevertebral fascia

Covers the prevertebral muscles both anteriorly and posteriorly - Attaches to the base of the cranium and to spinous processes and bodies of cervical vertebrae - Covers many of the deep nerves and vessels of the neck - Passes into the posterior mediastinum inferiorly - Cervical spinal nerves (ventral rami) pass laterally through the prevertebral layer between the scalene muscles

SCALP

Covers the skull and extends from the supraorbital margins to the nuchal lines, and laterally to the zygomatic arches. *SCALP* 1. Skin 2. Connective Tissue (dense) 3. Aponeurosis (epicranial aponeurosis) 4. Loose connective tissue 5. Pericranium (external layer of periosteum)

Dura Mater Covers which Cranial Nerves?

Cranial nerves III, IV, V1 and 2, and VI and the internal carotid artery.

Neural Crest Migration Problems can Result in...

Craniofacial anomalies such as clefts

Superior deep/jugulodigastric and Inferior deep/jugulo-omohyoid

Deep cervical lymph nodes grouped according to the muscle to which they are associated - Submental and submandibular lymph nodes drain the lips, chin, and tongue - Lymph nodes along the IJV drain the nuchal region and laryngo-tracheo-thyroid region

Prevertebral Muscles

Deepest structures in the neck Arise from and insert into the cervical vertebral bodies and transverse processes 2 overlapping muscles are named in this region, both primary neck flexors: - *Longus colli (longus cervicis)* - *Longus capitis* Prevertebral muscles are covered by prevertebral fascia and are important landmarks for the sympathetic trunks

Pharyngeal Arch Five

Degenerates

Intra-Oral Approach

Dentists who wish to completely block V2 often use the intra-oral approach of injecting an anesthetic agent into the pterygopalatine fossa via the greater palatine foramen and canal. - Angled needle is advanced 25-30 mm up the greater palatine canal and an anesthetic solution is injected, flooding the pterygopalatine fossa (sounds about as fun as having a root canal!) - Profoundly blocks V2, allowing the dentist to work on teeth anywhere in the upper quadrants

Carotid Sub-Triangle Borders

Digastric posterior belly, omohyoid superior belly, and anterior border of SCM. Its floor consists of the thyrohyoid, hyoglossus, and all three pharyngeal constrictor muscles

Bony Prominence of the Facial Canal

Distal to the genu, the facial nerve passes posteriorly in the facial canal midway between the tympanic cavity and the bony cochlea. As it does so, the facial canal produces the bony prominence of the facial canal on the upper medial wall of the tympanic cavity.

Cervical Viscera in the Neck

Divided into 3 different layers 1.) Endocrine layer (Anterior) - Thyroids, Parathyroids 2.) Respiratory layer (Middle) - Larynx, Trachea 3.) Digestive (Alimentary) layer (Posterior) - Pharynx, Esophagus

Dosal Surface (Dorsum) of Tongue

Divided into an anterior and posterior part by a V-shaped groove called the *terminal sulcus* that points posteriorly to the foramen cecum

Nasal Septum

Divides the nasal cavity into right and left parts - Posteriorly, the septum is bony - Anteriorly, it is cartilaginous Lined by a mucous membrane with an outer layer of respiratory epithelium

Pouch IV

Doral process = Superior parathyroid gland Ventral Process = Ultimobranchial Body

Pouch III

Dorsal process = Inferior parathyroid gland Ventral process = Thymus

CN IV Trochlear Nerve Arises from..

Dorsal side of midbrain - exit from the posterior surface of the midbrain below the inferior colliculus

Cerebral Veins

Drain blood from the brain into the dural sinuses

Submental Nodes

Drain the central lower lip, chin, floor of the mouth, tip of the tongue, and the lower central incisor teeth

Parotid Nodes

Drain the eyelids, front of the scalp, and the external auditory meatus, and part of the external ear

Posterior (Retro) Auricular Nodes

Drain the lateral & posterior scalp and most of the external ear

Occipital Nodes

Drain the posterior scalp and neck

Submandibular Nodes

Drain the side of the nose, the cheek, the entire upper lip, outer part of the lower lip, the gums, and most of the sides of the tongue

Internal Jugular Vein (IJV)

Drains brain, anterior face, cervical viscera, and deep muscles of the neck - Begins at the jugular foramen and runs in the carotid sheath with the ICA, CCA, and CN X. It leaves the anterior triangle when it passes deep to the SCM. - Unites with the subclavian vein to form the brachiocephalic vein, posterior to the sternal end of the clavicle. Its inferior end has a dilation (the inferior bulb), and has a valve

Ptosis

Drooping eyelid due to CN III dysfunction affecting Levator Palpebrae Muscle

Oculomotor Nerve Palsy

Drooping of the upper eyelid (Ptosis), dilatation of the pupil, *abduction*, and depression of the pupil (Quizlet def)

Dural Venous Sinuses

Dural Sinuses Cerebral Veins Jugular Foramen Specific Dural Venous Sinuses

Pharyngeal Arches and Cranial Nerves (or CN branch)

Each Pharyngeal Arch has a Cranial Nerve (or CN branch)

Pharyngeal Arches and Aortic Arch Arteries

Each Pharyngeal Arch has an Aortic Arch Artery

Nasal Cavity Lateral Wall

Each lateral wall of the nasal cavity consists of 3-4 *Turbinate Bones (conchae)* - These increase the surface area of the lateral nasal wall. 1.) Supreme (not always present) 2.) Superior 3.) Middle, all part of the ethmoid 1-3 all part of Ethmoid bone 4.) Inferior turbinate - largest concha and is a separate bone

Gray Rami Communicantes

Each spinal nerve receives a GRC from the adjacent Paravertebral Ganglion of the sympathetic trunk *Sympathetic postganglionic fibers* that connect sympathetic trunk ganglia with spinal nerves are collectively called the _____. - Some Cervical ganglia and Thoracic ganglia send gray rami communicantes directly to the heart

Epiglottis

Elastic cartilage covered by a mucous membrane; functions to cover the larynx when swallowing

Vocal Ligament

Elastic, thickened free upper edge (of conus elasticus?) Attachments: inner surface of the thyroid cartilage anteriorly; vocal process of the arytenoid cartilage posteriorly - Skeleton for vocal fold

Venous Drainage of the Scalp

Emissary veins: connection of *superficial veins* (same names as the arteries) --> to *emissary veins* --> to *diplöic veins* (course across the flat cranial bones) --> into *dural venous sinuses* (of the cranial cavity) - Dural venous sinuses will drain into the *internal jugular veins* Emissary veins can act as possible routes to transmit infections into the brain.

Signal Nodes/Virchow Nodes

Enlarged supraclavicular nodes are usually a bad sign. When enlarged, clinicians call them "signal nodes" or "Virchow's nodes". - Enlarged supraclavicular nodes on the left side are termed "Troisier's sign" - an indication of deposits of cancer cells that have spread from an obscurely located primary cancer, usually of the stomach. - Enlarged supraclavicular nodes on the right side often are indicative of lung carcinoma.

Laryngocele

Enlargement of the ventricular saccule may produce a diverticulum called a...

Thoracic Duct

Enters the neck through the superior thoracic aperture, just behind the esophagus. It arches to the left, behind the carotid sheath and anterior to the arterial branches of the subclavian artery, the anterior scalene muscle, and the phrenic nerve Usually empties into the junction of the *left subclavian and internal jugular veins*

Laryngeal Inlet

Entrance to the larynx anterior to the laryngopharynx; anterior border is formed by the free margin of the epiglottis - Aryepiglottic folds: lateral mucosal borders of the inlet extending from arytenoid cartilage to the epiglottis Posterior to the root of the tongue and the hyoid; forms the superior part of the anterior wall

Hyoepiglottic Ligament

Epiglottis attachment to the hyoid anteriorly

Larynx Structures/Spaces Visible on Exam

Epiglottis, vestibule, aryepiglottic folds with corniculate and cuneiform tubercles, vestibular folds, and vocal folds

Examination with an Otoscope

Examination of the tympanic membrane is done with an otoscope. Since the external acoustic meatus is not straight, clinicians gently pull the auricle upward and backward (in adults) to straighten it out. When a healthy membrane is illuminated, it appears pearly gray with a concavity directed inward - its concavity produces a "*cone of light" that projects anteriorly and inferiorly*

External Acoustic Meatus

Extends from Concha to the Tympanic membrane - Not straight: somewhat S-shaped and has 3 parts: 1.)Lateral part is directed anteriorly (this is why you have the earpieces of a stethoscope pointed forward toward your nose when you place them in your ears) 2.) Middle part is directed posteriorly 3.) Medial portion again turns anteriorly

Posterior Triangle Veins

External Jugular Vein Subclavian Vein

Innervation of the External Nose

External Nasal Nerve (from Anterior Ethmoid off of CN V1) carries innervation from the Bridge of the nose. Nasal branches of the Infraorbital nerve (from Maxillary Nerve) innervate Side of nose.

Tympanic part of temporal bone

External acoustic meatus

Parotid Gland Blood Supply

External carotid artery divides within the gland into its terminal branches: - Maxillary Artery - Superficial Temporal Artery

Collecting Sound Waves

External ear provides parts for collecting sound waves and directing them into the head where they move the eardrum (tympanic membrane).

Arterial Supply to the Face

Facial Artery (primary blood supply to face) - Inferior and Superior Labial Arteries - Lateral Nasal Artery - Angular Artery Transverse Facial Artery Supraorbital Artery Infraorbital Artery Mental Artery

Nerves Associated with the Tympanic Cavity

Facial Nerve Chorda Tympani branch of Facial n Nerve to Stapedius branch of Facial n Tympanic Nerve Plexus - Tympanic Nerve - Caroticotympanc Nerves (from Internal Crotid Plexus)

CN VII

Facial Nerve The facial nerve arises from the *Pontomedullary Junction* in two parts (large Motor Root and small Nervus intermedius) *General sensory*: Skin of external ear (small),Taste buds on anterior 2/3 of tongue + palate *Visceral motor (parasympathetic)*: Salivary and lacrimal glands *Skeletal motor*: Muscles of facial expression and others

Facial Nerve and Internal Acoustic Meatus

Facial Nerve leaves the cranial cavity and enters the *petrous* part of the temporal bone through the internal acoustic meatus along with the *Vestibulocochlear* nerve (CN VIII) At the lateral end of the meatus, the facial nerve enters the *facial canal*, where it is contained until it leaves the skull via the *stylomastoid foramen*

Second Arch Cranial Nerve

Facial nerve (cranial nerve VII) ("Smile")

Bell's Palsy

Facial paralysis due to damage of the facial nerve. In some cases it may be caused by swelling of the nerve due to the herpes simplex virus - About 80% of patients with Bell's palsy recover within 3 months

Cleft Palate

Fairly common, occurring in 1/2500 births and more often in females (67%) (Cleft lip is more common 1/1000 births and 80% affected are males) Occur posterior to the incisive fossa and can impair feeding and speech. They can also be associated with other birth defects and maternal use of anticonvulsant medications.

Vibrissae

Filter inhaled air

Pterygoid canal (paired)

Find this tricky canal inferior to the foramen rotundum, where the pterygoid process, greater wing, and body of the sphenoid unite. They are hidden in an articulated dried skull.

Pharyngeal Membranes Develop into...

First pair of pharyngeal membranes produces the tympanic membranes (eardrums). The others do not form any definitive adult structures.

Fistula vs Sinus vs Cyst

Fistula has two openings Sinus has one opening Cyst is a sac containing a liquid or semisolid material without any openings

Floor of the Oral Cavity Proper

Floor of the mouth contains the free part of the tongue and covered by a mucous membrane that covers a number of soft tissue structures: - Genioglossus (tongue muscle) - medially - Sublingual salivary glands - laterally - Geniohyoid and mylohyoid (deep to the above - can be considered the subfloor of the mouth) - Fauces - posteriorly (communicates with the oropharynx - covered later)

Lateral cervical cysts (aka - branchial cysts)

Fluid- or debris-filled masses that develop from persistent cervical sinuses. Present in the neck along anterior border of the sternocleidomastoid muscle. - Find a mass along the anterior border of the SCM in the lateral neck of a youngster or pre-teen? Think lateral cervical cyst.

Veins of the Nasal Septum

Follow the arterial distribution and terminate in either the pharyngeal or pterygoid plexuses of veins

Inferior Orbital Fissure

Foramen Rotundum Pharyngeal/Palatovaginal Canal Pterygoid Canal Palantine Canal

Second Arch Neural Crest Cells

Form the cartilage of the second arch (*Reichert's cartilage*) From the cartilage develops: - *S*tapes (middle ear), - *S*tyloid process of the temporal bone - *S*tylohyoid ligament Lesser Horns & Upper part of the Body of the Hyoid bone

Tympanic Cavity (Middle Ear) Medial Wall

Formed by a thin layer of bone that separates the tympanic cavity from the internal ear Features: - Promonotory - Tympanic Plexus - Round Window - Oval Window - Process Cochleariformis - Prominence of the Facial Canal

Kiesselbach's plexus

Formed by anastamoses of 5 Nasal Septum arteries Source of most minor nosebleeds (anterior epistaxis) Functions to warm the air passing into the nasal cavity

Development of the Parotid Gland

Formed by invagination of facial ectoderm in the groove between the maxillary and mandibular prominences. - This ectoderm pinches off from the surface of the face, but maintains a connection to the angle of the embryonic mouth = *future parotid duct* - When the mouth reduces in size, the duct loses it connection to the angle of the mouth, but retains its connection to the oral cavity, now opening opposite the 2nd upper molar

Cranial Cavity

Formed by the neurocranium and houses and protects components of the CNS. - Neurocranium is a box around the brain (including the meninges and some nerves and vessels) and is made of single frontal, sphenoid, ethmoid and occipital bones; and paired parietal and temporal bones.

Frontonasal Prominence (Single)

Formed from mesenchyme that proliferates rostral to the developing brain, it gives rise to the forehead and the nose (V1 innervation) - Nasal Pits - Medial Nasal Prominences Fuse

Tympanic Cavity (Middle Ear) Lateral Wall

Formed mainly by the tympanic membrane Chorda Tympani nerve crosses the lateral wall, passing between the handle of the malleus and the long process of the incus

Right Lymph Duct

Formed on the right side by the union of the *Left jugular, left subclavian, and the left bronchomediastinal lymph trunks* --> Enters the junction of the right subclavian and internal jugular veins - Frequently, the trunks do not unite to form the right lymph duct, but drain independently to the venous system

Retromandibular Vein

Formed within the Parotid gland by the union of the *superficial temporal and maxillary veins*

Palate

Forms roof of the mouth and separates the oral cavity from the nasal cavities Divided into the hard (anterior 2/3) and soft (posterior 1/3) palates

Pharyngeal Pouches

Four Outpocketings Of The Pharynx Lined By Endoderm The endoderm of the pharynx lines the inner aspect of the pharyngeal arches and forms a series of diverticuli (pouches) that protrude laterally between the arches. Four pouches develop; pouches III and IV each form dorsal and ventral processes. Later, the pouches give rise to the following adult structures:

Internal Nasal Branch of Anterior Ethmoidal

From *CN V1* Supplies the anterior region of the Lateral Nasal Wall

Dorsal Scapular Nerve

From C5, supplies the rhomboid muscles and the levator scapulae muscle.

Lesser Petrosal Nerve

From Tympanic Plexus Supplies preganglionic parasympathetic fibers to the otic ganglion

Roots of the Brachial Plexus

From Ventral Rami of spinal nerves C5-C8 and T1 Roots pass through the space between the anterior and middle scalene muscles - Twigs from the roots supply the *Prevertebral muscles and the scalene muscles* Two good-sized nerves are given off from the roots: 1.) *Dorsal scapular nerve*, from C5, supplies the rhomboid muscles and the levator scapulae muscle. 2.) *Long thoracic nerve*:C5-C7 roots, supplies the serratus anterior muscle.

Orbital Blowout Fracture

From blunt trauma by an object larger in diameter than the orbit (tennis ball, fist, dashboard) - Increased intraorbital pressure is transmitted to the weakest point (the inferior orbital wall) Contents of the orbit are entrapped and can have symptoms: 1.) *Inferior rectus palsy*: gives vertical diplopia (double vision when looking up 2.) *Infraorbital nerve palsy*: numbness of the cheek and upper gum on the affected side *Treatment* usually done as an outpatient after 2 weeks when edema is improved

CN VII Facial Nerve Arises

From the Pontomedullary junction in two parts: - Motor root of VII (larger) = skeletal motor fibers - Nervus intermedius (smaller)

Greater Palatine Nerve

From: Pterygopalatine ganglion (Branches of V2) To: *Hard Palate* - Posterior Inferior Lateral Nasal Nerves to Lateral Nasal Wall

7 Bones of the Orbital Margins

Frontal Zygomatic Sphenoid Maxilla Lacrimal Orbital Plate of Ethmoid, Sphenoid, and Palatine (all count as 1 apparently)

Lateral Orbit Bones

Frontal Zygomatic Sphenoid

Paranasal Sinuses

Frontal Sinuses Ethmoidal Cells Maxilary Sinuses

Choanae

Funnel-shaped openings, especially of the posterior nares; one of the communicating passageways between the nasal fossae and the pharynx.

Ethmoid infundibulum

Funnel-shaped passageway, opens into the semilunar hiatus. The maxillary sinus and some anterior ethmoid sinuses drain here

Optic Nerves

Gangion Cell Axons from Retina to Optic Chiasma - pass through optic canal (entrance to cranial cavity) on the way to the Chiasma

CN VII Facial Nerve: General Sensory Component

General sensation from a small patch of skin on the concha of the external ear is thought be carried in CN VII. Cell bodies of these afferent neurons are in the *geniculate ganglion of VII* - Not very clear on how these nerve fibers reach the external ear - they may hook up with the auricular branch of CN X (vagus)

CNX Vagus Basic Components

General sensory - skin of the external ear + external surface of eardrum. General sensory - mucous membranes of lower pharynx and of larynx. Special sensory - taste buds on epiglottis. Visceral motor (parasympathetic) - Cardiac muscle, smooth muscle, and glands in organs of thorax and abdomen. Visceral sensory - thoracic & abdominal organs Skeletal motor - soft palate, pharynx & larynx muscles.

CN IX Glossopharyngeal Nerve General Sensory Component

General sensory fibers supply the mucous membranes of the middle ear cavity = tympanic cavity (including the internal surface of the tympanic membrane), the posterior 1/3 of the tongue, the fauces (= junction between oral cavity and pharynx) which contains the palatine tonsils, the soft palate, and the upper pharynx. Sore throat pain is transmitted through CN IX.

CN V Functional Components

General sensory: skin of the face and mucous membranes of the nasal cavity & mouth Skeletal motor: Mastication (chewing) muscles and others

Ethmoidal Sinus Drainage

Generally 20-24 Ethmoidal Air Sinuse Note their proximity to the orbit. They are *separated from it only by the lamina orbitalis of the ethmoid bone*. They have different drainage points: a. The anterior ethmoidal sinuses drain into the middle meatus via the infundibulum. b. The middle ethmoidal sinuses into the middle meatus. c. The posterior ethmoidal sinuses drain into superior meatus.

Fourth and Sixth Arches Aortic Arch Arteries

Give rise to arteries in the thorax - 4th aortic arches --> the proximal part of the right subclavian artery and a portion of the arch of the aorta - 6th aortic arches --> proximal portions of the pulmonary arteries and embryonic ductus arteriosus

First Pharyngeal Clefts

Give rise to the external acoustic (auditory) meatuses. The second, third, and fourth pharyngeal clefts are overgrown by the second pharyngeal arch when the smooth neck forms. Subsequently, they fuse to form the cervical sinus, a potential space that normally obliterates later in development.

Maxillary prominences (paired)

Give rise to the upper jaw (V2 innervation). - Fusion with the lateral nasal prominences gives a smooth transition from cheek to nose - Fusion with the intermaxillary segment completes the upper lip

Ossicle Movement

Given that the tympanic membrane has a much larger surface area than the base of the stapes, the movements of the ossicles *amplify the smallest movements of the tympanic membrane* (up to 20x), so that great force is produced at the oval window by only small movements of the tympanic membrane

Second Arch Mesenchyme from Paraxial Mesoderm

Gives rise to its associated muscles - Mimetic muscles (muscles of facial expression - "Smile") - Posterior belly of the Digastric Muscle - Stylohyoid muscle - Stapedius muscle (middle ear)

First Arch Mesenchyme from Paraxial Mesoderm

Gives rise to muscles associated with the first arch: - Muscles of mastication (chewing muscles) - Mylohyoid - Anterior belly of the Digastric - Tensor tympani (middle ear) - Tensor veli palatini (soft palate)

Fourth and Sixth Arches Mesenchyme from Paraxial Mesoderm

Gives rise to muscles: - Pharyngeal constrictor muscles (superior, middle, and inferior), - Intrinsic muscles of the larynx (muscles of phonation = produce sound) - Levator veli palatini (soft palate) - Palatoglossus muscles (of the tongue)

CN IX

Glossopharyngeal Nerve Sensory to the posterior tongue and to the pharynx. Innervates one muscle: Stylopharyngeus [tylopharyngeus muscle is way too Stylish for "vague" (vagal) innervation, she's always "dressed to the nines" (CN IX innervated)] - Sore throat pain - Tonsillitis pain - Afferent limb of the "gag" reflex - *Blood pressure/blood gases information from carotid artery receptors*

Third Arch Cranial Nerve

Glossopharyngeal nerve (cranial nerve IX).

Palate Blood Supply

Greater palatine artery --> hard palate Lesser palatine artery --> soft palate

Palantine Foramen

Hard Palate Medial to the 3rd molars, the *greater palatine foramen* pierces the palate and just posterior to this is the *lesser palatine foramen*

Incisive Fossa

Hard Palate a depression in the midline just posterior to the central incisors

Anterior Tongue Mucosa

Has a rough texture because of the presence of numerous lingual papillae

Subclavian Arteries

Have different origins, but similar courses in the root of the neck. Both subclavian arteries pass anterior to the lung apices and their associated cervical pleura. Branches of the subclavian are best studied by dividing the artery into 3 parts: - *Part I*: between its origin and the medial border of anterior scalene - *Part II*: lies behind anterior scalene - *Part III*: between lateral border of anterior scalene and 1st rib Beyond the 1st rib, the subclavian artery is known as the *Axillary Artery* Typical arrangement of the subclavian has it giving off 4 branches, all of which arise from the first part

Water's View Imaging

Head is slightly extended as if getting a drink of "Water"!

Basilar part of occipital bone

Helps to form the Clivus (in the cranial cavity) Pharyngeal tubercle

Arterial Supply to Scalp

Highly vascularized from vessels that branched off the *External Carotid Artery*, and include: - Superficial temporal - Posterior auricular - Occipital Branches of the *Ophthalmic Artery* (from internal carotid artery) serve anterior parts of scalp - Supraorbital artery - Supratrochlear artery

Pharyngeal Arch Two

Hyoid Arch

CN XII

Hypoglossal Nerve Skeletal motor: innervates all muscles of the tongue - both intrinsic and extrinsic - except one (the palatoglossus muscle) Arises as many rootlets from the *medulla - between the pyramid and the olive* (all tongue muscles are innervated by the "Hippo-glossus" except the Palato-glosss bc if a hippo stepped on a pallet it would break!)

Surgeons have devised a scheme for dividing the palpable cervical lymph nodes into seven regions or "levels"

I - Submental and submandibular nodes. II - Upper deep cervical nodes III - Middle deep cervical nodes IV - Lower deep cervical nodes V - Nodes in the posterior triangle VI - Nodes in the muscular triangle

Names of Cranial Nerves 1-6

I = Olfactory II = Optic III = Oculomotor IV = Trochlear V = Trigeminal VI = Abducens

Sensory (S), Motor (M), or Both (B) - Mnemonic

I Some II Say III Marry IV Money V But VI My VII Brother VIII Says IX Big X Boobs/Brains XI Matter XII Most

Which cranial nerves pass through the Cavernous Sinus

III, IV, VI, V1, V2

Carotid Triangle Clinical Relevancy

Important for many reasons: taking a carotid pulse; and any surgical procedure to access the common carotid or its branches, IJV, the Vagus or hypoglossal nerves. Atherosclerotic plaques are common and the access point to remove the plaque is through the carotid triangle.

Submandibular Glands (and Innervation)

In close relationship to the mandible, mostly inferior and medial to it. - They are both superficial and deep to the mylohyoid muscle Submandibular duct (~2in long) opens onto a small sublingual papilla beside the base of the lingual frenulum *Innervation:* presynaptic PS Secretomotor fibers from the Facial Nerve via the Chorda Tympani with Postsynaptic neurons in the Submandibular Ganglion (CN lecture).]

Posterior Triangle Brachial Plexus

In the Posterior Neck Triangle, several of the Roots unite to form the *Trunks* of the brachial plexus - *Upper Trunk*: Roots C5-C6 - *Middle Trunk*: Root C7 - *Lower Trunk:* Roots C8 and T1 One nerve is given off from the upper trunk: the *Suprascapular Nerve* (Supplies supraspinatus and infraspinatus ) No branches arise from the other trunks

Ciliary Ganglion

In the ganglion, preganglionic parasympathetic fibers synapse; these fibers are coming from the Edinger-Westphal nucleus. Off the ciliary ganglion emerge short ciliary nerves that contain both postganglionic sympathetic and parasympathetic fibers. The postganglionic parasympathetic fibers are going to sphincter papillae and the ciliary muscles.

Septal Cartilage with 2 Lateral Processes

In the midline; forms the Anterior part of the nasal septum - Trauma to this cartilage, causing deviation, may block the flow of air into the nasal cavity Left and right lateral processes articulate above with the nasal bones

Oral Region

Includes the oral cavity, teeth, gingivae, tongue, palate, and the region of the palatine tonsils. Food is broken down by the teeth and mixes with saliva from the salivary glands to create a bolus that is then swallowed, a process known as deglutition

Major Viscera in the Neck

Includes: Thyroids and Parathyroids Larynx and Trachea, Pharynx and Esophagus - All the viscera are covered by the *Pretracheal Layer* of deep cervical fascia and lie in the floor of the muscular triangle deep to the sternohyoid and sternothyroid muscles

Facial Clefts

Incomplete or partial fusion of the facial prominences. The most common craniofacial anomalies.

Condylar Canal

Inconstant = for an emissary vein

Otitis Media

Infection of the mucosa in the tympanic cavity Pathogens gain entrance to the tympanic cavity by ascending through the pharyngotympanic tube from the pharynx Causes bulging and redness of the tympanic membrane - Pharyngotympanic tube in infants is about 1/2 length of adults and is oriented more horizontally. Because of this, otitis media is more common in young children

Nuchal Lines (Paired)

Inferior and Superior

Venous Drainage of the Larynx

Inferior and superior laryngeal veins, then into superior, middle, or inferior thyroid veins - Submucosal (microscopic) venous plexus also drains some of the blood

Clinically Important Orbit Relationships

Inferior: maxillary sinus Superior: frontal sinus, ACF, ethmoid cells Medial: ethmoid cells Deeper: sphenoid sinus, MCF, optic chiasm, pituitary, cavernous sinus, PPF

Levator Palpebrae

Inserts into the upper eyelid and is responsible for *Elevating the upper lid* thus opening the eye, Innervated by *CN III (oculomotor)* - Near the anterior end of the levator muscle some smooth muscle fibers are present CALLED *Superior Tarsal Muscle*. These fibers also assist in opening the lid, and in a disease called Horner's syndrome, where there is an *interruption in the sympathetic supply* to head and neck and to these fibers, ptosis may also be present.

Scalenus Anterior

Inserts onto first rib On its surface is the phrenic nerve Subclavian vein passes anterior, the subclavian artery passes behind it.

Bony Labyrinth

Interconnected cavities within the petrous temporal bone. Lined by a periosteum and filled with a fluid called perilymph.

Membranous Labyrinth

Interconnected series of ducts and sacs constructed of dense connective tissue lined internally by an epithelium Suspended within the bony labyrinth and separated from the bony walls by the perilymph. Filled with *Endolymph*!!!!

2 Pairs of Arteries that supply the brain

Internal Carotid Artery (ICA) and Vertebral Arteries

*Internal carotid arteries and Dural Sinuses*

Internal carotid arteries pass through the sinuses and turn forward (coronal section shows the artery as a circle). Note that venous blood is surrounding arterial blood in the cavernous sinuses. How odd!

Structures that enter or leave the pharynx: *Between the middle and inferior pharyngeal constrictors*

Internal laryngeal n. Superior laryngeal a. and v.

Thyroid Lymphatic Drainage

Into Paratracheal and deep cervical nodes

Anterior Ethmoidal Sinuses Drain

Into the middle meatus via the infundibulum

Ethmoid Bone

Irregularly shaped, spongy bone that provides the floor of the front part of the skull and the roof of the nasal cavity - Creates a "Labyrinth" by creating the *Conchae*

Lymphatic Drainage of the Larynx

Jugulodigastric nodes and/or the paratracheal nodes, then inferior deep cervical nodes

Body of Sphenoid Bone

Jugum (articulates with the ethmoid bone) Sella turcica - Tuberculum sellae - Hypophysial fossa - Dorsum sellae - Posterior clinoid processes Sphenoidal sinus (paired but rarely symmetrical - see the hemiskull)

Parasympathetic Fibers Associated with V3 - *Otic Ganglion Postganglionic*

Just inferior to foramen ovale in the infratemporal fossa, V3 is connected to the Otic Ganglion (parasympathetic ganglion) *Postganglionic fibers hitch a ride on the auriculotemporal nerve of V3 to the parotid gland. These secretomotor fibers stimulate the parotid to secrete saliva*

Parasympathetic Fibers Associated with V3 - *Otic Ganglion Preganglionic*

Just inferior to foramen ovale in the infratemporal fossa, V3 is connected to the Otic Ganglion (parasympathetic ganglion) *Preganglionic parasympathetic fibers derived from the glossopharyngeal nerve (IX) synapse here*

Lacrimal Apparatus

Lacrimal gland = tear gland ("laCRYmal gland") - Lies in upper lateral part of orbit relating to the superior rectus and levator palpebrae superioris muscles Innervated by the *Facial Nerve* via a very, very circuitous route

Vallate Papillae

Large, flat-topped. Anterior to the terminal sulcus. Surrounded by trenches whose walls are covered by taste buds. Serous glands of the tongue also open into these trenches. has tasebuds

Posterior Cranial Fossa (PCF)

Largest and deepest fossa, mainly in the occipital bone - Dorsum sellae: separates the PCF from the hypophysial fossa - Clivus slides down to the foramen magnum - Internal occipital crest separates the cerebellar hemispheres *Contents* - Cerebellum - Pons - Medulla

Pterygopalatine Ganglion (PPG)

Largest of the 4 *Parasympathetic* ganglia in the head, contains the largest aggregation of neurons in the head outside the brain. Associated with *Cranial Nerve VII* - Contains the cell bodies of *postganglionic parasympathetic* neurons, whose axons are *Secretomotor to the lacrimal gland, nasal glands, and glands of the hard and soft palates* - branches of V2 pass through or around the ganglion. These nerves reach V2 via the ganglionic branches that suspend the pterygopalatine ganglion in the pterygopalatine fossa

Parotid Gland

Largest salivary gland - Lies in the depression between the ramus of the mandible and the sternocleidomastoid muscle, surrounded by a capsule of deep fascia Shaped like a double pyramid. - When viewed on the face, it is wider above and tapers down to an apex near the sternocleidomastoid. - When viewed in horizontal section, it has a wide superficial part, external to the mandible and masseter muscle, and a narrow deep part, wedged between the ramus of the mandible, mastoid process, and styloid process. - The deep part of the gland may contact the pharynx.

External Acoustic Meatus: Construction

Lateral 1/3: Cartilage wall that is continuous with the cartilage of the auricle and it is lined by skin Medial 2/3: Bony wall (*tympanic portion of the temporal bone*) lined by skin

Carotid Triangle Common Pathologies

Lateral Cervical Cyst Carotid body tumor Pharyngeal diverticulum Laryngocele

Muscular Triangle Common Pathologies

Lateral cervical cyst

If the Cervical Sinus Persists ...

Lateral cervical cyst (branchial cleft cyst) may develop

Aryepiglottic Folds

Lateral mucosal borders of the inlet extending from arytenoid cartilage to the epiglottis

Glabella

Latin = "smooth"; region between the superciliary arches

CN VI Abducens Nerve Arises...

Leaves the brainstem at the junction of the pons and medulla

Nerve to Stapedius

Leaves the facial canal, passes through the temporal bone, and supplies the stapedius muscle - which is in a bony canal adjacent to the middle ear cavity

Superior Deep Cervical Nodes (Arrangement)

Lie alongside the Internal Jugular Vein, superior to the omohyoid muscle One node in this group is given a special name: *Jugulodigastric Node*

Semicircular Ducts

Lie inside the semicircular canals Where the ducts meet there are enlargements called *Ampullae* - Receptors within the ampullae monitor *angular acceleration of the head (head rotation)*

Cervicothoracic Ganglion (Stellate Ganglion)

Lies anterior to the neck of the 1st rib Formed by the fusion of the first thoracic ganglion and the lowest cervical ganglion - If these two are Not fused, then lowest cervical ganglion is known individually as the inferior cervical ganglion

Subclavian Artery Part II

Lies behind the anterior scalene muscle

Oral Cavity Proper

Lies between the maxillary (upper) and mandibular (lower) dental arches (arcades) - Roof is the palate. - Floor of the mouth contains the free part of the tongue and covered by a mucous membrane that covers a number of soft tissue structures:

Digestive Layer - Cercival Esophagus

Lies immediately behind trachea, commencing below the pharynx at the level of *C6* Recurrent laryngeal nerve passes upward in the groove between the esophagus and the trachea Paratracheal lymph nodes also lie between the trachea and esophagus

Sympathetic Trunk

Lies posterior to the carotid sheath, behind the prevertebral fascia, and anterior to the longus capitis muscle. - Unlike in the thorax, it does NOT have chain ganglia associated with each spinal nerve. Instead, the *original eight embryonic ganglia* have fused into *3-4 cervical chain ganglia* - Much variation in their arrangement.

Pretracheal Fascia

Limited to anterior neck - Attaches to the hyoid and laryngeal cartilages superiorly and *blends with the fibrous pericardium in the thorax inferiorly* 2 parts: 1.) Muscular: thin and surrounds the infrahyoid muscles 2.) Visceral: surrounds the thyroid gland, trachea, and esophagus - Attaches to the thyroid cartilage superiorly, and extends down into the anterior mediastinum

Nasal Cavity Mucous Membrane and Venous Plexus

Lines the meati and conchae. Has numerous mucous glands, and cilia, which beat downward and inferiorly with wave-like action. Also contains a massive venous plexus that can dilate rapidly when irritated - Irritation also causes sneezing and mucous production. - Engorgement of these vessels may block airflow through the meati. This venous plexus reacts so quickly that it has been called *erectile tissue* --> rhinitis etc

Tympanic Plexus of Nerves

Located in the mucous membrane on the promontory in the tympanic cavity Receives contributions from: - Tympanic Nerve (from CN IX) - Caroticotympanic Nerves Sensory branches of the plexus (from Tympanic n) supply Mucosa of the tympanic cavity, inner aspect of the tympanic cavity, mastoid antrum, mastoid air cells, and the pharyngotympanic tube Also gives off the *Lesser petrosal nerve*

Parotid Duct (Stensen's Duct)

Located parallel to the tip of the ear lobule - Crosses the masseter muscle, pierces the buccal fat pad and the buccinator, and empties into the oral cavity adjacent to the second upper molar - Accessory glandular tissue may lie along its course

Cutaneous sensory branches of the cervical plexus: C1-4

Location: deep to the SCM; nerve loops that lie anteromedial on the levator scapula and middle scalene Superficial branches: are cutaneous (C1-4) that pass into the skin just posterior to the midpoint (Erb's Point) of the SCM - Blockage of these nerves with an anesthetic agent at this location will deaden sensation in a wide area of the neck

Ansa cervicalis

Loop of motor nerve fibers from cervical plexus that serves almost all infrahyoid muscles (except Thyrohyoid) - Superior root: C1 fibers ride and loop down from CN XII - Inferior root: C2, 3 (C1 fibers that hitch a ride on CN XII to innervate the thyrohyoid and geniohyoid muscles are NOT part of the ansa cervicalis)

Pars Flaccida

Loose part of Tympanic Membrane above mallear folds where the membrane has no middle layer

Supraclavicular Lymph Nodes

Lymph nodes: part of inferior deep nodes, drain superficial cervical nodes - Left side: *receive drainage from the internal organs via the thoracic duct* These are one of the first visible locations where advanced metastasis occurs from internal organs (called "sentinel" LNs by some clinicians). However, enlarged supraclavicular nodes could also result from breast cancer, esophageal cancer, lymphoma, or even an infection in the arm

Skeletal Framework - Facial Skeleton

Mandible Maxillae Zygomatic bones Nasal bones Lacrimal bones Palatine bones Inferior nasal conchae Vomer

Pierre Robin Sequence

Manifestation of First Arch Syndrome

Treacher Collins Syndrome

Manifestation of First Arch Syndrome

Floor of Orbit Bones

Maxilla

Medial Orbit Bones

Maxilla Frontal Lacrimal Ethmoid Sphenoid Palatine "My Fun Little Eye Sits Patiently in the orbit"

Inferior Orbit Bones

Maxilla Zygomatic

Ectopic Thyroid Tissue

May be found on the back of the tongue (lingual thyroid), and the neck region (thyroid) - Because the thyroid forms in the back of the tongue and later moves into the neck, ectopic tissue is reasonably common

Polyps in the Nasal Cavity

May be result of Chronic Inflammation (e.g. allergic rhinitis)

Fracture of the Cribiform Plate

May cause cerebrospinal fluid (CSF) to leak into the nasal cavity. This is called CSF rhinorrhea. The Halo sign is pathognomonic. So if a head trauma patient complains of a runny nose - check it out! You don't want to miss a CSF leak!

Fracture of the cribriform plate

May result in anosmia (inability to smell) due to damage of the olfactory nerve fibers.

Mobile part of the Nasal Septum

Medial crura, joined together in the midline of the noses with some connective tissue, form the mobile part of the nasal septum, located between the two nostrils

Anterior Triangle Boundaries

Medial: anterior midline of neck Posterior: SCM Superior: inferior border of the mandible Apex: jugular notch Roof: subcutaneous tissue with the platysma Floor: pharynx, larynx, and thyroid gland - Recall the hyoid lies in the anterior triangle opposite C3. The anterior triangle above and below the hyoid bone are often called suprahyoid and infrahyoid regions, respectively Vessels: External carotid artery (ECA) system & IJV: see "Carotid Triangle"

Structures/spaces within the petrous temporal bone

Middle ear (Tympanic cavity + auditory ossicles). Internal ear (contains receptors for hearing and balance). Carotid canal (contains the internal carotid artery and internal carotid autonomic plexus). Facial canal (contains the facial nerve).

Amplifying Sound

Middle ear contains tiny bones (*auditory ossicles*) that move when the eardrum moves, amplify the sound waves, and convert the movement of air into movement of fluid in the internal ear.

Neural Crest Migration

Migration Of Cranial Neural Crest Into Pharyngeal Arches & Subsequent Epithelial-Mesenchymal Interactions Are Crucial To Head & Neck Development

Puncta

Minute Orifices in which Lacrimal canaliculi commence - On the summits of the papillae lacrimales, seen on the margins of the lids at the lateral extremity of the lacus lacrimalis - 2 in the medial (inside) portion of each eye Function to collect tears produced by the lacrimal glands

Tongue (3 Parts)

Mobile muscular organ that can assume a variety of shapes and positions for articulation, moving food into the pharynx, mastication and taste 1.) *Root*: attached portion between the mandible, hyoid and the posterior surface of the tongue 2.) *Body*: anterior portion between the root and the apex 3.) *Apex (tip)*: the anterior end of the body that rests against the incisors Body and apex are extremely mobile!

Tarsal Glands

Modified sebaceous glands that lie in the tarsal plate and secrete an oily substance into an opening behind the free edge of the lid

Ceruminous glands

Modified sweat glands that produce a brown, semisolid fatty/waxy substance called cerumen (ear wax!)

Muscles of Facial Expression (Mimetic Muscles)

Most act to dilate or constrict the orifices they surround. - Originate from bone or fascia and insert into the facial skin - Most of the muscles are quite superficial. One exception is the buccinator, which is separated from the superficial muscles by the buccal fat pad. Groups: - Muscles of the forehead - Muscles about the orbit - Muscles about the mouth - Muscles of the nose

External Carotid Artery

Most branches originate in the carotid or submandibular triangles *Middle branch*: ascending pharyngeal ascends on the pharynx, supplies it, the prevertebral muscles, middle ear, and cranial meninges 3 Anterior branches: - Superior Thyroid a - Lingual a - Facial a 2 Posterior branches: - Occipital a - Posterior Auricular a

Supraclavicular Lymph Nodes

Most inferior group of inferior deep cervical nodes Nodes have connections with lymphatic vessels that drain the upper limb (via axillary nodes) and the mediastinum and lungs (via tracheal nodes and connections to the bronchomediastinal lymph trunks), as well as those that drain the scalp, head, and neck Lymph from abdominal organs can make its way to the supraclavicular nodes via connections to the thoracic duct on the left side of the body --> may be involved with carcinoma originating anywhere in the head and neck, and within the thoracic and abdominal cavities

Frostbite

Most of the auricle has little fat and CT, so the ear is easily susceptible to frostbite

Innervation of the Auricle

Most of the auricle is supplied by the *Great Auricular Nerve* (from the cervical plexus) and *Auriculotemporal Nerve (from V3)* - Tiny contributions to the skin of the concha are made by twigs from the *facial and vagus nerves*

Fourth and Sixth Arches Lateral Plate Mesoderm

Most of the cartilages of the larynx (except epiglottis) are formed from the embryonic cartilages of the 4th and 6th p.arches. However - these cartilages do NOT come from neural crest but are derived from lateral plate mesoderm - epiglottis may be derived from mesenchyme that migrates into the larynx at a later time.

Deep Fascia of the Face

Most of the face has no definitive deep fascia. Therefore, the facial skin is particularly mobile A discernable layer of deep fascia does cover the masseter muscle and envelops the parotid gland, forming its capsule.

Facial Veins and Infection

Most veins in the head are valveless, providing potential routes for the spread of infection.

Blood Supply of the Lateral Nasal Wall

Mostly from *Lateral Nasal Branches of the Sphenopalatine Artery* that enters the nasal cavity posteriorly through the sphenopalatine foramen - This artery is believed to be involved when there is a serious *nosebleed* Other arteries in the lateral nasal wall are *Anterior and Posterior Ethmoid Arteries*, both off the ophthalmic.

Sensory Innervation of the Lateral Nasal Wall

Mostly from CN V2, via the *Pterygopalatine ganglion* Specific branches are 1.) Lateral Posterior (nasal) branches 2.) Internal Nasal Branch of Anterior Ethmoidal (from V1) 3.) Nasal Branches of the Infraorbital Nerve (a branch of V2) - supply the area of the vestibule. 4.) Also: Olfactory nerve

CN IX Glossopharyngeal Nerve Motor Component

Motor fibers in CN IX supply one skeletal muscle =the stylopharyngeus- which elevates the pharynx during swallowing Cell bodies are in the *nucleus ambiguus in the medulla*

CN VI Abducens Nerve Pathway

Motor nucleus in *Lower (Caudal) Pons* 1.) Leaves the brainstem at the junction of the pons and medulla 2.) Passes superiorly and penetrates dura 3.) Then bends sharply forward (90°) across the petrous part of the temporal bone to enter the cavernous sinus 4.) Runs within the center of the sinus alongside the internal carotid artery 5.) Enters the orbit through the *Superior orbital fissure* 6.) Enters the medial surface of the lateral rectus muscle

CN IV Trochlear Nerve Pathway

Motor nucleus in midbrain 1.) Motor fibers *decussate within midbrain* then exit from the posterior surface of the midbrain below the inferior colliculus 2.) Nerve is very longer and slender - it winds around the midbrain and like CN III it passes between the posterior cerebral and superior cerebellar arteries.. 3.) Then traverses the cavernous sinus 4.) Enters the orbit through the *Superior orbital fissure* 5.) Penetrates the superior surface of the superior oblique muscle

CN VII Facial Nerve: Skeletal Motor Component

Motor nucleus is in *Pons* - Axons of these neurons make up the motor root of VII. Motor rootsupplies the muscles of *facial expression* (mimetic muscles), as well as the *stapedius muscle* in the middle ear and two muscles in the upper neck: the *stylohyoid muscle and posterior belly of the digastric muscle* Also contains *proprioceptor afferent fibers* from these muscles

Scalp Auricular Muscles and Innervation

Move auricle Supplied by *Posterior Auricular branch of CN VII*

Extra-Ocular (Skeletal) Muscles

Move the eyeball in the orbit. Both eyes function together producing conjoint visual responses - 4 Recti (superior, inferior, lateral, medial) - 2 Oblique muscles (inferior, superior) - Levator palpebrae (which acts on the eyelid, not the eyeball)

Extrinsic Laryngeal Muscles

Move the larynx as a whole: - Infrahyoid muscles depress it; - Suprahyoid muscles and Stylopharyngeus muscle elevate it

Arytenoid Cartilages

Movement of the arytenoid cartilages abduct or adduct the vocal ligaments, thus widening or narrowing the space between the vocal folds Corniculate Cartilage Vocal Process Muscular Process Crico-arytenoid Joints

Innervation of the Tympanic Cavity (Middle Ear)

Mucosa is supplied by the *Tympanic branch* of the *Glossopharyngeal nerve (CN IX)* - Pain from a middle ear infection is carried in CN IX

Oral Leukoplakia

Mucous membrane condition characterized by the appearance of white plaques that do not rub off. They can be precancerous and there should be a high index of suspicion in individuals with risk factors for oral cancers (smokers, heavy drinkers). Must be biopsied in order to diagnose and treat.

Fungiform Papillae

Mushroom-shaped scattered about has tasebuds

Internal Carotied Artery

NO Branches in the Neck

White Rami Communicantes

NOT IN CERVICAL GANGLION

Named Regions of the Face

Nasal Oral Orbital Infra-orbital Supra-orbital Buccal Zygomatic Mental Parotid

Nerves that Join the Pterygopalatine Ganglion

Nerve of the Pterygoid Canal (Vidian n.) "That Pesky Chick Vivian is always joining in..."

CN XI Accessory Nerve Pathway

Nucleus in *Ventral Gray of Spinal Cord C1-6* 1.) Passes through the middle part of the jugular foramen usually in the same dural sheath as the vagus 2.) Crosses superficial to the internal jugular vein from medial to lateral then passes deep to the styloid process and posterior belly of the digastric muscle 3.) Enters the deep surface of the Sternocleidomastoid (SCM), which it innervates 4.) Leaves the posterior border of SCM about at its midpoint to enter the posterior triangle of the neck 5.) Crosses the posterior triangle obliquely (vulnerable) then enters the anterior border of Trapezius.

Tympanic Membrane Orientation

Obliquely situated - external surface faces anterior and inferior - This means the anterior wall and floor of the external acoustic meatus are longer than the posterior wall and roof

Posterior Triangle Subdivisions

Occipital Omoclavicular

SVC Syndrome

Occlusion: engorgement of superficial veins draining head & neck Causes: Cancer, thrombosis from indwelling central venous catheter Symptoms and Signs: Dyspnea, headache, facial edema, venous distension in neck

Transformation of the Pharyngeal Arches Overview

Occurs during the 5th week when the second arches migrate caudally to overgrow the third and fourth arches and fuse with the upper part of the thorax. - This overgrowth covers up and internalizes the second, third, and fourth pharyngeal clefts, to produce the smooth contour of the neck as it connects the head to the upper thorax. Internalization and fusion the caudal three pharyngeal clefts forms bilateral potential spaces in the developing neck called cervical sinuses. Normally the cervical sinuses obliterate .. but we know well enough that these kinds of things don't always happen!

CN 3

Oculomotor Nerve Components: *Skeletal motor*: to 4 extraocular muscles + levator palpebrae superioris muscle *Visceral motor*: parasympathetic 1.) PreG fibers synapse in the ciliary ganglion 2.) Post G fibers innervate ciliary muscle and constrictor pupillae m. (smooth muscles) in eyeball

Thoracic Duct Receives Lymph from...

Often receives lymph from the *Left jugular, left subclavian, and the left bronchomediastinal lymph trunks* However, any of these may enter the venous system independently

Cranial Nerve Mnemonic

Oh Once One Takes The Anatomy Final Very Good Vacations Are Heavenly

CN I

Olfactory Nerve Special sensory = Smell

Rima Glottidis

Opening between the two true vocal folds - Median cricothyroid ligament reinforces it anteriorly

Oval Window (fenestra vestibuli)

Opening into the internal ear - Footplate of the stapes fits into the oval window - Above and behind the promontory

CN V Has Three Divisions ("Three Twins")

Ophthalmic (V1) Maxillary (V2) Mandibular (V3)

CN II

Optic Nerve Special sensory = Vision - Optic Nerves - Optic Chiasma - Optic Tracts

Optic canal (paired)

Optic canal (paired)

Optical Axis vs Orbit Acix

Optical Axis is straight Orbit Axis is at 45 degree angle laterally

Preganglionic Sympathetic Fibers to the Head and Neck...

Originate from: Intermediolateral cell column of the upper thoracic spinal cord segments (*T1- T3*) Enter the sympathetic trunk through *white rami communicantes* - Preganglionic fibers ascend through the sympathetic trunk to the *superior cervical ganglion*, situated opposite *C2 vertebra*. Here they synapse on postganglionic sympathetic efferent neurons

C1 Fibers and CN XII

Other C1 fibers join CN XII and "ride-it" forward into the neck. These C1 motor fibers leave the hypoglossal to innervate the geniohyoid muscle in the floor of the mouth and the thyrohyoid muscle in the neck (an infrahyoid or "strap" muscle).

Are Cranial Nerves PNS or CNS?

PNS

Corniculate and Cuneiform Cartilages

Paired and lie within the mucous membranes of the aryepiglottic folds, where they are called tubercles. They should be seen in a laryngoscopy, are somewhat insignificant, but may give support to these folds

Skeleton of the Nose

Paired nasal bones, at the upper part of the dorsum, which contribute to the bridge - frontal and maxillary bones also contribute to its structure

Internal Longitudinal Pharyngeal Muscles

Palatopharyngeus Stylopharyngeus* Salpingopharyngeus - All innervated by Vagus (CN X) EXCEPT Stylopharyngeus (CN IX Inervation) - "too Stylish for Vague innervation"

Zygomatic Nerve

Parallels the main trunk of V2 into the orbit via the inferior orbital fissure. Passes along the lateral wall of the orbit and divides into *zygomaticofacial and zygomaticotemporal branches*

Inferior Laryngeal Nerve Damage

Paralysis of *Ispilateral* Vocal Folds

Chronic Sinusitis

Paranasal Sinus Mucosal membrane Infection Chronic sinusitis may produce meningitis, brain abscesses, osteomyelitis, cavernous sinus thrombosis, or orbital cellulitis

Posterior Superior Alveolar Nerves

Pass through the pterygomaxillary fissure, skirt the infratemporal fossa, and penetrate the body of the maxilla - Carry *sensation from the maxillary sinus, upper posterior teeth and associated gingivae*

V1 Opthalmic Nerve Pathway

Passes anteriorly in the lateral wall of the cavernous sinus and enters the orbit through the superior orbital fissure - Near the superior orbital fissure V1 divides into the frontal, nasociliary, and lacrimal nerves

Superior Orbital Fissure

Passes from a medial to a superolateral position Tansmits *Cranial nerves III, IV, VI, and branches of V1 (Lacrimal, Frontal and Nasociliary)* - The *Ophthalmic Veins* usually pass into the superior orbital fissure as well

Facial Nerve

Passes through the bony facial canal above the medial wall of the tympanic cavity - thus, the facial nerve runs within the temporal bone midway between the middle and internal ear

Deep Cervical Nodes Receive Lymph from...

Peripheral (outlying) nodes in the head and neck - Peripheral nodes can be roughly organized into superficial and deep groups

Bony Septum

Perpendicular plate of the Ethmoid, Vomer, and Nasal crests of the Maxilla and Palatine bones form the inferior part of the septum - Superiorly, bony nasal septum joins Sphenoid, Frontal, and Nasal Bones - Posteriorly, Vomer forms the medial bony wall of the Choanae or posterior nares

Functions of the Larynx

Phonation (sound production) ≠ speech production - Regulates amount of air entering the trachea and lungs - Acts as a valve to prevent ingested food from entering the airway

Cavernous Sinus and Associations Pic

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Cavernous Sinus and Pterygoid Plexus Pic

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External Jugular Vein

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Facial Vein

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Intermaxillary Segment

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Lateral cervical cysts (aka - branchial cysts) MRI

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Mental Artery

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Philtrum of the upper lip

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Posterior Auricular Vein

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Pterygopalatine Fossa MRI

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Relationship of thyroid and recurrent laryngeal nerves

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Supraorbital and Infraorbital Arteries

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Topography of Nerves Entering the Orbit

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Botox and Collagen

Plastic surgeons use injectable collagen to smooth out wrinkles and creases and botulinum toxin to temporarily paralyze specific facial muscles to reduce previous skin creasing and avoid new creasing.

Superficial Cervical Fascia/Subcutaneous tissue of the Neck Contents

Platysma muscle Superficial Veins *External jugular vein (EJV) Anterior jugular veins* Cutaneous sensory branches of the cervical plexus: C1-4

Posterior and Anterior Communications of PPF

Posterior Communications: - Foramen Rotundum - Pterygoid Canal - Pharyngeal Canal Anterior Communications: - Interior Orbital Fissure Inferior Communication: - Palantine Canal

Medial Lateral Borders of PPF

Posterior Communications: - Pteromaxillary Fissure Anterior Communications: - Sphenopalantine Foramen Inferior Communication: - Palantine Canal

Innervation of Posterior Ethmoid Air Cells and Sphenoid

Posterior Ethmoid Nerve

Laryngopharynx

Posterior to the larynx Extends from the tip of the epiglottis to the inferior border of the cricoid cartilage where it becomes continuous with the esophagus - Relates to the bodies of *C4-C6* vertebrae Posterior/lateral walls formed by the middle and inferior pharyngeal constrictor muscles Features - Laryngeal inlet - the communication with the larynx - Piriform recess - a depression on either side of the laryngeal inlet

Nasopharynx

Posterior to the nose and superior to the soft palate - Respiratory function - Opens from nasal cavity via the choanae - Bounded by the base of the skull and the soft palate Features: - Pharyngeal Tonsil - Salipingopharyngeal Fold - Tubal Tonsil - Torus of the PT tube - Pharyngeal Recess

Facial Canal and Stylomastoid Foramen

Posterior to the tympanic cavity, the facial canal bends inferiorly and descends between the tympanic cavity and mastoid air cells to the stylomastoid foramen.

Innervation of Maxillary Air Sinus

Posterior, Middle, and Anterior Superior Alveolar

Posterior Triangle Boundaries

Posterior: anterior border of trapezius Anterior: posterior border of SCM Inferior: middle third of the clavicle Apex: where the SCM and trapezius meet on the superior nuchal line Roof: investing layer of deep cervical fascia Floor: prevertebral fascia on the splenius capitis, levator scapulae, middle and posterior scalene muscles

Vasomotor Fibers

Postganglionic Sympathetic nerve fibers to Blood Vessels

Sudomotor Fibers

Postganglionic Sympathetic nerve fibers to Sweat Glands

Autonomic Nerves

Postsynaptic Sympathetic Pre and Postsynaptic Parasympathetic General Sensory

Pterygopalatine ganglion and V2 Blocks: Intranasal Approach

Preferred approach - An applicator soaked with anesthetic solution is placed posterior to the middle nasal concha for ~20-30 minutes, allowing the anesthetic to diffuse through the nasal mucosa into the pterygopalatine fossa

CN III Parasympathetic Component

Preganglionic parasympathetic Cell bodies in *Edinger-Westphal Nucleus* in the *Midbrain* - Preganglionic fibers follow oculomotor nerve, then the inferior division, to synapse in Ciliary ganglion within the orbit - Postganglionic fibers reach eyeball through the short Ciliary nerves These fibers cause contraction of smooth muscle in the ciliary muscle (accommodation: shaping the lens so that objects nearby come into focus) and stimulating smooth muscle in the constrictor pupillae (constricting pupils)

Nerve of the Pterygoid Canal (Vidian Nerve)

Preganglionic parasympathetic fibers, derived from the Greater Petrosal Nerve (from CN VII), enter the Pterygopalatine Ganglia as a component of the (Vidian Nerve) Composite nerve, composed of *Postganglionic Sympathetic Fibers (from the Deep Petrosal Nerve) and Preganglionic Parasympathetic Fibers from the Greater Petrosal* - Sympathetic fibers pass directly through the ganglion, subsequently hitching rides on branches of V2 to their targets

Endocrine Layer Lymphatic Drainage (Thyroid AND Parathyroid)

Prelaryngeal Pretracheal Paratracheal

Arterial Supply to the Orbit

Primarily via the Opthalmic Artery

Inferior Rectus Function

Primary: *Depress* Secondary: *Adduct and Extorsion*

Superior Rectus Function

Primary: *Elevate* Secondary: *Adduct and Intorsion*

Inferior Oblique Function

Primary: *Extorision* Secondary: *Elevate and Abduct*

Superior Oblique Function

Primary: *Intorsion* Secondary: *Depress and Abduct*

Third Arch Mesenchyme from Paraxial Mesoderm

Produces only one muscle: Stylopharyngeus muscle of the pharynx

Pressure in the Tympanic Cavity

Produces pain - by compressing the highly sensitive tympanic membrane Interferes with hearing (conductive hearing loss)

Third Arch Neural Crest

Produces the cartilage of the third arch. From this cartilage develops the greater horn and the lower part of the body of the hyoid bone

Tragus

Prominent projection just anterior to the opening of the external acoustic meatus - *Antitragus*: a bump on the inferior part of the antihelix posterior to and opposite the tragus ( from Greek for goat - presumably because ear hair resembles the beard on the chin of a goat)

Stapedius Action

Pulls the neck of the stapes posteriorly and tightens up the annular ligament to prevent excessive movement of this tiny bone

Bony Orbit

Pyramid-shaped cavity - Infra-orbital Margin formed by Maxillary Bones - Supra-orbital margins formed by Frontal Bones - Margin of each orbit is composed of 7 bones, some of which are found in different parts of the orbit *Lateral*: frontal, zygomatic and sphenoid *Inferior*: maxilla and zygomatic *Roof*: frontal *Floor*: maxilla *Medial*: frontal, maxilla, lacrimal, orbital plate of ethmoid, sphenoid and palatine

Annulus Tendineus Communis (Ring of Zinn)

Recti muscles arise from a common tendinous ring that surrounds the optic canal and lies over the superior orbital fissure - Each rectus muscle passes forward from the ring and eventually inserts into the sclera of the eyeball. - Together the 4 recti form a tendinous cone that encloses the optic nerve. The ring is often called the ___________

Structures that enter or leave the pharynx: *Inferior to the inferior pharyngeal constrictor*

Recurrent laryngeal nerve (1) Inferior laryngeal artery (2)

Tensor Tympani Action

Reduces the vibrations of the malleus and movements of the tympanic membrane by pulling the malleus and tympanic membrane medially (thus tensing the tympanic membrane).

Second Arch Aortic Arch Artery

Regresses as the second pharyngeal arch develops. Its only vestige is the small *stapedial artery* of the middle ear.

Thyroarytenoid Muscle

Relaxes the Vocal Ligament (by shortening the distance between attachment and insertion)

Horner's Syndrome

Results from disruption of the sympathetic outflow to the orbit or to head and neck and to smooth muscle fibers of the *Anterior Levator* - May happen as a result of neck surgery (carotid artery) or a tumor that invades the sympathetic chain in the upper chest (Pancoast tumor - often from the lung). Triad: *Miosis*: pupil constriction (opposite is mydriasis: pupil dilation - unopposed parasympathetics) *Ptosis*: drooping of the upper lid *Anhidrosis*: absence of sweating

Venous Drainage of Parotid Gland

Retromandibular Vein - Superficial Temporal Vein - Maxillary Vein Posterior Auricular Vein External Jugular Vein Facial Vein

Pharyngeal Lymphatic (Waldeyer's) Ring

Ringformed by the Palatine, Lingual, Tubal and Pharyngeal Tonsils. Protective barrier against infection in the first few years of life

Pharyngotympanic Tube (Eustachian/Auditory Tube)

Runs anteriorly and medially from the tympanic cavity to nasopharynx Posterolateral 1/3: Bony Rest has a cartilaginous wall. Tube normally closed, but when it opens (facilitated by yawning or swallowing) air can pass through, and this equalizes pressure between the tympanic cavity and the atmosphere.

Superior Oblique of Eye

Runs from the sphenoid bone passing forward through the fibrocartilaginous pulley to course backward into the sclera Innervation is from *Trochlear (CN IV)*

Dura Mater Meningeal Layer

Same as that surrounding the spinal cord - It reflects away from the periosteal layer, forming partitions that separate the cranial cavity into compartments

Vestibular Nerve Receptors are in..

Semicircular Ducts, Utricle & Saccule

V2 Maxillary Nerve

Sensory nerve Supplies meninges in the cranial cavity, the upper teeth and gums, mucosa in the oral cavity and on the palate, the maxillary air sinus, and skin of the upper cheek, side of the nose, lower eyelid, upper lip, and the "temple" area on the side of the head.

V1 Opthalmic Nerve

Sensory nerve Supplies the eyeball, conjunctiva, some of the nasal mucosa, the frontal air sinus, and skin of the external nose, upper eyelid, forehead and anterior scalp

Bucal Fat Pad

Separates buccinator from the superficial muscles This fat pad is prominent in infants, giving them the typical cherubic appearance. This is not so desirable in adults. Thus, buccal fat pad reductions seem to be popular in the cosmetic surgery circles.

Cartilaginous Nasal Septum

Septal, the medial crus of the greater alar, and the Vomeronasal cartilages form the cartilaginous nasal septum

Anterior Cranial Fossa (ACF)

Shelf lying superior to the orbits and nasal cavity - Frontal bone: orbital plates - Ethmoid bone: cribriform plates, crista galli - Sphenoid bone: lesser wings (posterior boundary of the ACF) *Contents* - Frontal lobe of the cerebrum - Olfactory bulbs lie on either side of the crista galli - Cranial nerve I axons pass through cribriform plates *Foramen*: Cribiform Plate (CN I Olfactory N)

Process Cochleariformis

Shelf of bone derived from the anterior wall extends onto the medial wall, forming a platform on which the tensor tympani muscle is supported. The end of this bony shelf produces a curved tip, the *processes cochleariformis*, which acts a *pulley for the tendon of the tensor tympani* = the tendon bends laterally around it to reach its attachment to the handle of the malleus - Located above the promontory and the oval window

Cauliflower Ear

Skin and elastic cartilage become separated by hematomas (blood clots) due to chronic trauma (boxers, wrestlers) auricle becomes misshaped and wrinkled over time

External Acoustic Meatus: Skin

Skin lining the external acoustic meatus contains hair follicles, sebaceous glands, and ceruminous glands

Eyelid Structure

Skin on outside and a mucous membrane on the inside called the *Conjunctiva* - Eyelashes: short curved hairs on the free edges of the lids, usually arranged in triple or double rows - At the base of lashes are *Sebaceous Glands of Zeis* - *Tarsal Glands* - Closed by *orbicularis oculi* - Upper lid opened by *Levator Palpebrae* - Joined by Medial and Lateral Angles

Branchial Sinuses

Small canals that open onto the lateral neck along the anterior border of the sternocleidomastoid (external branchial sinus) or into the pharynx near the tonsillar fossa (internal branchial sinus). Result from incomplete fusion of the 2nd pharyngeal arch as it grows caudally over the 3rd and 4th arches (external sinus) or rupture of the second pharyngeal membrane (internal sinus). - If the sinus connects to a lateral cervical cyst, the sinus may "weep" fluid

Foliate Papillae

Small lateral folds of mucosa. Poorly developed in humans. has tasebuds

Sublingual Glands

Smallest and deepest of the salivary glands. Create a horseshoe-shaped mass around the lingual frenulum and lie between the mandible and the genioglossus muscle - Numerous sublingual ducts open into the floor of the mouth along the sublingual folds

Iris

Smooth muscle fibers that either open the pupil (dilator pupillae), or close the pupil (sphincter pupillae) - *Short Ciliary nerves* (postganglionic parasympathetics) from the ciliary ganglion innervate the sphincter pupillae smooth muscles fibers - Ciliary ganglia are where the preganglionic parasympathetic fibers synapse from the CN III (oculomotor) - *Long Ciliary Nerve* (postganglionic sympathetic) innervates the dilator pupillae via nasociliary branch of CN V1 (ophthalmic)

Swallowing (Deglutition)

Solid food is chewed and mixed with saliva to form a soft bolus that is easy to swallow o Stage 1 - Voluntary. The food bolus is compressed against the palate and pushed into the oropharynx (mainly by muscles of the tongue/soft palate) o Stage 2 - Involuntary and rapid. The soft palate elevates, sealing off the nasopharynx. The pharynx widens and shortens as the suprahyoid and longitudinal pharyngeal muscles contract, elevating the larynx o Stage 3 - Involuntary. Sequential contractions of all three constrictors that force the bolus into the esophagus

Brachial Plexus

Somatic nerve plexus Originates in the root of the neck and terminates in the axilla, where it gives off large nerves that supply the upper limb - Smaller branches of the plexus are given off in the neck, supplying muscles of the pectoral girdle, primarily those that move the scapula

Laryngeal Sphincter Muscles

Some muscles can also act as sphincters, bringing the ary-epiglottic folds together: - Transverse Arytenoid - Oblique Arytenoid - Aryepiglottic

Tympanic Membrane Shape and Umbo

Somewhat coned-shaped - External surface is concave and the internal surface convex and bowed inward - *Umbo*: Peak of the cone is - attached to the handle of the malleus

Sound: Auricle --> Tympanic Membrane

Sound waves are collected by the auricle and concentrated in the external acoustic meatus. The tympanic membrane moves in response to the sound waves in the air. Since the malleus is attached to the internal surface of the membrane, movements of the tympanic membrane produce movements in the tiny bones (ossicles) in the middle ear.

Palperbral Fissure

Space between the eyelids

Oral Vestibule

Space between the lips/cheeks (externally) and the teeth/gingivae (internally) - Communicates with the outside of the body via the rima oris (oral fissure)

Rima Vestibuli

Space between the vestibular folds

Meatus (Pl: Meati)

Spaces beneath the Conchae (named accordingly): 1.) Supreme meatus (sometimes present) 2.) Superior meatus 3.) Middle meatus 4.) Inferior meatus

CN XI

Spinal Accessory Nerve Skeletal motor: innervates sternocleidomastoid and trapezius muscles Does NOT arise from the brainstem - instead the motor nuclei are in the upper six cervical spinal cord segments. Ascends into the skull via *Foramen Magnum* Exits via *Jugular Canal*

Sternocleidomastoid muscle (SCM)

Sternal head: round tendon attaches to the manubrium Clavicular head: attaches to the medial 1/3 of the clavicle - Lesser supraclavicular fossa: space between the heads; supraclavicular lymph nodes Proximal attachment: mastoid process and superior nuchal line *Separates the anterior triangle from the posterior triangle* Unilateral contraction: lateral neck flexion and rotates the head so the face is turned superiorly toward the opposite side Bilateral contraction: flexes the neck to bring the chin to the thorax

Muscles of the Triangles

Sternocleidomastoid muscle (SCM) Trapezius muscle Suprahyoid muscles Infrahyoid muscles Deep cervical/Prevertebral muscles

Vestibular Ganglion

Stimulation of receptor cells in the vestibular organs (semicircular ducts, sacule, utricle) produces action potentials in neurons of the *vestibular division of the vestibulocochlear nerve (CN VIII)* - These are bipolar neurons with cell bodies in the vestibular ganglion (Scarpa's ganglion)

Structures that enter or leave the pharynx: *Between the superior and middle pharyngeal constrictors*

Stylopharyngeus Glossopharyngeal n. (CN IX) Stylohyoid ligament

Submandibular Triangle Common Pathologies

Submandibular gland tumor

Anterior Triangle Sub-Triangles

Submental Sub-Triangle Submandibular Sub-Triangle Muscular Sub-Triangle Carotid Sub-Triangle

Quadrangular Membrane

Submucosal sheet of elastic tissue, extending between the lateral parts of the arytenoid and epiglottic cartilages Superior free margins in aryepiglottic folds form "Aryepiglottic Ligament" Inferior free margins in aryepiglottic folds form "Vestibular Ligament"

Blood Supply to the Auricle

Superficial temporal and posterior auricular arteries (both from the external carotid)

Blood Supply of the External Acoustic Meatus

Superficial temporal, posterior auricular, and deep auricular (from the maxillary) arteries

Deep Cervical Lymph Nodes

Superior Group - Jugulodigastric Node Inferior Group - Jugulo-Omohyoid Node - Supraclavicular Node Receives lymph from Superficial and Deep Peripheral Nodes of head and neck

Anterior Triangle Nerves

Superior Laryngeal Nerve Ansa Cervicalis Transverse Cervical CN X, XI, XII Vagus Nerve Branches - Pharyngeal Branches - Carotid Branches - Superior Laryngeal Branches - Recurrent Laryngeal Nerves

Specific Dural Venous Sinuses

Superior Sagittal Inferior Sagittal Straight Confluence of Sinuses Transverse Sigmoid Occipital Cavernous - Intercavernous Superior Petrosal Inferior Petrosal Middle Meningeal Artery

Venous Drainage of Thyroid

Superior and Middle Thyroid Veins --> drain into Internal Jugular Veins and Inferior Thyroid Veins --> usually drain directly into Brachiocephalic Veins below

Thyroid Cartilage

Superior border at *C4* Largest but incomplete cartilage - entirely open posteriorly *Laminae*: 2 fused in the midline; form the *laryngeal prominence* - Attachment of inferior constrictor muscles *Oblique line*: attachment for the sternothyroid and thyrohyoid muscles *Superior horn*: connected superiorly to the hyoid bone via the thyrohyoid membrane *Inferior horn*: articulates with the cricoid cartilage at the cricothyroid joints, which help to adjust the length of the vocal folds

Pharynx

Superior part of the alimentary canal posterior to the nasal and oral cavities extending inferiorly past the larynx Extends from base of skull to the cricoid cartilage anteriorly and inferior border of C6 vertebra posteriorly where it is continuous with the esophagus 3 Parts: - Nasopharynx - Oropharynx - Laryngopharynx

Superior Root of the *Ansa Cervicalis* and CN XII

Superior root of the *ansa cervicalis* joins CN XII - superior root contains motor fibers from C1 - After hitching a ride, the superior root leaves XII to join the inferior root - thus completing a loop-like nerve called the ansa cervicali Ansa innervates *Infrahyoid* muscles in the neck.

Occipital Posterior Triangle

Superior to omohyoid inferior belly Major contents: External Jugular Vein, occipital artery, posterior branches of the cervical plexus, CN XI, trunks of the brachial plexus, superior deep cervical nodes

External Circular Pharyngeal Muscles

Superior, Middle and Inferior Pharyngeal Constrictors - All innervated by Vagus (CN X)

Innervation of Recti Muscles

Superior, Middle, Inferior Recti: Oculomotor Nerve (CN III) Lateral Rectus: Abducent Nerve

Tympanic Cavity (Middle Ear) Posterior Wall

Superiorly is an opening called the *Aditus to the Mastoid Antrum* The mastoid antrum is a common cavity that communicates with a variable number of small mucosa-lined cavities called mastoid air cells. The antrum and air cells are within the mastoid process of the temporal bone. - Below the aditus is small, hollow, cone-shaped projection called the *Pyramid*, from whose apex emerges the tendon of the stapedius muscle

Olfactory Nerve Innervation of the Lateral Nasal Wall

Supplies general sensation to the epithelium of the Superior meatus and Concha just inferior to the cribriform plate - The receptors for olfaction (smell) are concentrated in this region; this is the reason we sniff in order to smell more effectively

V3 Mandibular Nerve Sensory Portion

Supplies the lower teeth and gums, mucous membranes in the oral cavity and on the tongue, and skin of the cheeks, lower lips, chin, external ear and middle scalp

V3 Mandibular Nerve Motor Portion

Supplies the muscles of mastication ( 4 muscles), the tensor tympani, tensor veli palatini, and mylohyoid muscles, and the anterior belly of the digastric muscle

Blood Supply of the External Nose

Supply from *Dorsal Nasal Artery* (branch of Ophthalmic Artery) and *branches from Facial Artery*

Lateral Posterior (nasal) Branches

Supply posterior region of lateral nasal wall

Posterior Triangle Arteries

Suprascapular Occipital Transverse/Superficial Cervical Subclavian (3rd part) ""SOTS - Super Odd Transvestite Substitutes"

Investing Fascia

Surrounds the entire neck just deep to the superficial fascia; forms a roof over the neck triangles - Splits to enclose the SCM and trapezius Stays divided: attaches to the anterior and posterior sides of the manubrium, forming a suprasternal space that encloses the inferior parts of the anterior jugular veins, the jugular venous arch, and some lymph nodes - Attachments: superior nuchal line, mastoid process, and spines of cervical vertebrae - Splits to enclose the submandibular glands and the parotid glands' fibrous capsules - Inferiorly attaches to the clavicle, manubrium, and scapula. Binds the inferior belly of the omohyoid to the clavicle

Cavernous Sinus MRI

T2 — nuclei out of alignment Fat dark, H2O bright

Sigmoid Sinus MRI

T2 — nuclei out of alignment Fat dark, H2O bright

Superior Sagittal Sinus MRI

T2 — nuclei out of alignment Fat dark, H2O bright

Transverse Sinus MRI

T2 — nuclei out of alignment Fat dark, H2O bright

CN IX Glossopharyngeal Nerve Tase Component

Taste buds on the posterior one-third of the tongue are carried in lingual branches of IX. Cell bodies of these afferent neurons are in the inferior ganglion of IX. Central processes of neurons synapse on cells in the nucleus of the solitary tract in the medulla.

CN VII Facial Nerve: Taste Component

Taste from the anterior 2/3 of the tongue is carried first in the lingual nerve (V3) then in the chorda tympani nerve of VII Cell bodies of these afferent neurons are in the *geniculate ganglion* of VII Central processes of the neurons pass into the brainstem via the nervus intermedius to synapse on the nucleus of the solitary tract in the medulla

CN VII Facial Nerve Terminal Branches

Temporal, zygomatic, buccal, mandibular, and cervical branches - These nerves spread across the face to supply the facial muscles (they make you smile, grin, grimace, pout, pucker, etc.).

Muscle of the Ossicles

Tensor tympani (CN V3 innervation) Stapedius (CN VIII) - Dampen movements of the ossicles (and tympanic membrane) in response to loud noises - Chronic loud noise fatigues them! (Tiny Tensor Tympani gets a Tiny nerve from Trigeminal V3, damage here makes you hear Thumder - sensitive to loud noises)

Failure to Fully Adduct Eye from Neutral or Elevate Eye from Adducted Position

Tests: Fully Adduct: isolating & testing: Medial Rectus Now elevate: isolating & testing: Inferior Oblique Failure of Either Indicates: *CN III Lesion*

Failure to Depress or Elevate Eye from Neutral

Tests: Inferior Rectus (Depress) and Superior Rectus (Elevate) Failure of Either Indicates: *CN III Damage*

Failure to Abduct Eye from Neutral

Tests: Lateral Rectus Failure Indicates: *CN VI Damage*

Failure to Depress Eye from Adducted Position

Tests: Superior Oblique Failure Indicates: *CN IV Lesion*

Pterygoid Venous Plexus and Sphenoid Emissary Vein

The *pterygoid venous plexus* communicates with the cavernous sinus via a small *sphenoid emissary vein( that passes through a tiny opening in the sphenoid bone. Thus - in a roundabout way, blood can pass from face to infratemporal fossa and then to the *Cavernous sinus*

The Contour of the Neck

The 2nd arch grows caudally over the 3rd and 4th arches - producing the smooth contour of the neck This process produces & internalizes a transient ectoderm-lined cervical sinus = the fused 2nd, 3rd and 4th pharyngeal clefts.

Lateral Nasal Wall when Conchae are Removed

The anatomy of the lateral nasal wall is exposed in greater detail when the conchae are removed. - Ethmoid bulla - Semilunar hiatus - Ethmoid infundibulum - Uncinate (Latin hook-like) Process - Frontal recess - Nasolacrimal orifice of the nasolacrimal duct

Vestibule

The anterior entrance to the nasal cavity is through the anterior nares that are partitioned by the mobile septum (columella). Internal to the nares there is a cavity, the vestibule, which is lined by skin with vibrissae (hairs) - Limen nasi, indicates the junction within the nasal cavity between the vestibule and the nasal cavity proper

Neurocranium

The bony "brain box" enclosing the cranial cavity and its contexts (brain, meninges and blood vessels).

Deep Cervical Nodes and Carotid Sheath

The deep cervical lymph nodes lie on the carotid sheath and often need to be removed when they become involved in cancer of head and neck structures. Because these nodes are intimately related to the internal jugular vein, it is often necessary to remove it as well.

Laryngitis

The mucous membrane in the ventricles has many mucous glands. In laryngitis these become enlarged and secrete an over-abundance of mucous, which covers the vocal folds. With the subsequent edema, it's hard to phonate and hoarseness results.

Roots and Branches

The other two components of the brachial plexus, the cords (formed by various combinations of the anterior and posterior divisions), and the terminal branches of the plexus, are found in the axilla, and are beyond the scope of this lecture

Genu of Facial Nerve

The part of the facial nerve that is bent from anterior to posterior in the facial canal

Pharyngeal Arches - Arches

The pharyngeal arches support the lateral walls of the pharynx (foregut). Six paired arches form originally; usually only five develop into adult structures.

Thoracic Outlet

The region between the clavicle and first rib, through which nerves and vessels reach the upper limb

Scalp Cutaneous Innervation

The skin is very sensitive. 1.) Trigeminal (CN V) - Supraorbital (V1) - Supratrochlear (V1) - Zygomaticotemporal (V2) - Auriculotemporal (V3) nerves 2.) Cervical plexus nerves, anterior rami: - Lesser occipital & Great auricular (both C2,3) 3.) Posterior rami cutaneous branches of C2 (Greater occipital) and C3 (Third occipital)

SCALP Proper

The skin, connective tissue, and aponeurosis (SCA, layers 1-3) make up the SCALP proper and are clinically considered one layer that are reflected together during a craniotomy, or when part of the SCALP is torn off in an injury.

Veins of the Orbit

The superior and inferior ophthalmic veins are tributaries of the facial vein - Both may spread infection from the face or teeth regions into the cavernous sinus resulting in a cavernous sinus thrombosis

Nose

The thing you sniff with (Memory Device: "sNiff" N = Nose!)

Auditory Ossicles

The three tiny ossicles extend across the tympanic cavity, covered in mucous membrane, from the tympanic membrane to the internal ear. From lateral to medial: - Malleus - Incus - Stapes

Endocrine Layer

The thyroid and parathyroid glands lie under the floor of the muscular triangle. A fibrous capsule derived from pretracheal fascia surrounds this complex *Thyroid gland (C5-C7)* - Median isthmus (2-4 tracheal rings) - Lateral lobes - Superior and Inferior poles *Parathyroid Glands* - Secrete parathyroid hormone (increases blood Ca levels; Stimulates osteoclasts to break down bone and release Ca) - Increases Gi Ca absorption - Antagonist to calcitonin - Usually 4

Development of the Thyroid Gland

The thyroid arises from *endoderm-lined pouch - the thyroglossal duct* - in the primitive pharynx at about *24 days* of development. It descends in the midline, *from the back (dorsum) of the tongue* where the foramen cecum remains as the vestigial opening, to the Anterior Neck 1.) Arises as proliferative center at root of tongue, at the foramen cecum, thus endodermally derived 2.) Descends as a bilobed diverticulum in front of pharynx, connected to tongue for a time by thyroglossal duct 3.) Eventually resides over larynx, with two lateral lobes and an isthmus (remnant of thyroglossal duct)

Vocal Fold Tumors

The vocal folds are common sites of tumors and nodules, which can produce hoarseness. These folds have no direct lymph drainage, so, if the tumor is malignant, early removal may prevent metastasis.

Lymph Drainage of Scalp

There are no lymph nodes in the scalp Lymph drains into nodes at the junction between the head and neck. Most of the scalp drains into *parotid, mastoid, and occipital nodes* and then into the *deep cervical lymph nodes* located along the internal jugular vein (IJV).

Fourth and Sixth Arches

These arches are usually considered together since they combine to give rise to the larynx.

Inferior Deep Cervical Nodes (Arrangement)

These are related to the lower part of the Internal Jugular Vein, at and below the point where it is cross by the Omohyoid. Jugulo-Omohyoid Node

Ectodermal placodes

Thickened regions of ectoderm that form the sensory ganglia of cranial nerves V, VII, IX and X

Midline of Neck Common Pathologies

Thyroglossal duct cyst Thyroid tumor Dermoid cyst

Foramen Cecum

Thyroglossal duct normally atrophies and closes off as the *foramen cecum* before birth but can remain open in some people

Blood Supply of the Tympanic Cavity (Middle Ear)

Tiny arteries supply blood to the tympanic cavity - Posterior tympanic artery from the posterior auricular artery - Anterior tympanic artery from the maxillary artery

Pouch II

Tonsillar fossa (later, mesenchyme invades the fossa to form the palatine tonsils)

Cornea

Transparent membrane covering the iris Sensitive to a number of modalities (pain, touch, pressure) which are carried by afferent fibers passing into the *Nasociliary nerve off of CN V1*, and into the *Trigeminal Ganglion* and brain stem to make central connections

Nasal Cavities

Triangular in shape, narrow superiorly and widen inferiorly. The openings are the anterior and posterior nares. From anterior to posterior the cavities are quite narrow - lies medial to the orbit and the maxillary air sinus, and inferior to the anterior cranial fossa. Note the important relationships of the ethmoid air sinuses to the medial wall of the orbit and the maxillary air sinuses to the orbit inferiorly

CN V

Trigeminal Nerve Largest cranial nerve Major sensory nerve of face Arises from the pons in two parts: - Sensory root (large) - Motor root (small)

Tympanic Membrane

Trilaminar oval structure that separates the external ear from the middle ear. Attached to a ring of bone belonging to the *tympanic part of the temporal bone* 3 Layers: 1.) *External surface*: of membrane lined by epidermis 2.) *Internal surface*: lined by a mucosa continuous with that of the tympanic cavity 3.) *Central core* of the membrane is a layer of connective tissue Layers are thin, membrane is semi-transparent

CN IV

Trochlear Nerve Skeletal motor: innervates the *superior oblique muscle* (extraocular eye muscle). - Arises from the *dorsal side of midbrain* ("four rhymes with dor") *Only motor nerve - cranial or spinal - that arises from the dorsal aspect of the CNS*

All Cranial Nerves attach to the Anterior (Ventral) Brain or Spinal Cord Except...

Trochlear Nerve (CN IV) which attaches to the Dorsal Side

Frey's Syndrome (sweating gustatory syndrome)

Twigs of CN IX nerve fibers can remain after surgical removal of the parotid, and they may regenerate and grow into the adjacent skin. Chewing certain foods may trigger these nerves that used to tell the parotid to secrete saliva. Instead, their stimulation may now call sweat glands into action (via the release of Ach), producing sweating of the skin over the parotid.

Caroticotympanic Nerves

Twigs that leave the *Internal Carotid Plexus* to enter the tympanic cavity through its anterior wall and join the tympanic plexus Contain postganglionic sympathetic nerve fibers that supply smooth muscle in blood vessels

Interior of the Larynx

Two mucosal folds project into the laryngeal cavity and define the spaces of the interior larynx - Vestibular folds ("false vocal cords") - Vocal folds

Eitympanic Recess ("Attic")

Tympanic cavity is taller than the external acoustic meatus and the tympanic membrane. The floor of the cavity is just about at the level of inferior border of the tympanic membrane, but the roof rises well above the upper border. This upper extension of the tympanic cavity is called the epitympanic recess, often referred to as the "attic".

Paired Greater Alar Cartilages

U-shaped structures that surround the nostrils - each greater alar cartilage has a lateral and medial crus Medial crura, joined together in the midline of the noses with some connective tissue, form the mobile part of the *Nasal Septum*, located between the two nostrils

First Arch Syndrome

Underdevelopment of the first pharyngeal arch can lead to varied malformations of the face: A collection of *malformations involving derivatives of the maxillary and mandibular prominences* - May include underdevelopment of the mandible or zygomatic bones, enlargement of the mouth, and malformations of the eyelids, ears, or palate - Failure of proliferation of neural crest or excessive cell death may be underlying factors.

LeFort Type II

Unilateral or bilateral fracture through the maxillae, infra-orbital foramina, lacrimal bones, and bridge of the nose. This produces a triangular fragment in the central face that is detached from the rest of the skull.

Thyroglossal Sinuses

Usually occur when a cyst enlarges and opens onto the skin anterior to the laryngeal cartilages

Thyroglossal Duct Cysts

Usually present in the midline of the neck Represent a persistent thyroglossal duct between the tongue and the neck (remnants of epithelium remain) which forms a cyst

What cranial nerve (division) innervates the inner cheeks and lips?

V2?

Mylohyoid (Innervation)

V3: nerve to mylohyoid

Stylohyoid (Innervation)

VII attaches to the hyoid bone at the greater horn

Names of Cranial Nerves 7-12

VII = Facial VIII = Vestibulocochlear IX = Glossopharyngeal X = Vagus XI = Spinal accessory XII = Hypoglossal

Fourth and Sixth Arches Nerves

Vagus nerves (X) - Superior laryngeal nerves = 4th arches - Recurrent laryngeal nerves = 6 arches

Costocervical Trunk

Variable and small but normally gives off 2 branches: - *Highest intercostal artery* - to the first two intercostal spaces - *Deep cervical artery* - anastomosis with the occipital artery, supplying deep extensor muscles of the neck

Veins of the Tongue

Veins: drain in a similar fashion as the artieres to the *Lingual vein* and into the *Internal jugular vein*

Allergic Rhinitis

Very common condition (up to 25% of the population) Result of exposure to an allergen and the resultant inflammatory cascade. Treatment is removal of the offending allergen and medical therapy for symptomatic relief (intranasal steroid sprays, antihistamines, immunotherapy, etc.)

CN VIII

Vestibulocochlear Nerve Special sensory = Balance and Hearing

Larynx Glottis

Vocal folds + Rima glottidis, the space between vocal folds

Tracheostomy

When Larynx is removed (Laryngectomy) because of laryngeal cancer, the trachea can be connected to an opening in the anterior neck via.....

Scalp Aponeurosis

When cut, the occipitofrontalis holds the wound open so lacerated arteries can't retract --> Scalp wounds bleed profusely. - Superficial lacerations that do not extend to the aponeurosis are easily closed

Anterior and Posterior Divisions (of the Retromandibular Vein)

Within (or below) the gland it divides into anterior and posterior divisions. The posterior division joins the posterior auricular vein to form the external jugular vein. The anterior division usually joins the facial vein.

Parasympathetic fibers associated with V2

Within the Pterygopalatine Fossa V2 is connected to the pterygopalatine ganglion (a parasympathetic ganglion) - Preganglionic parasympathetic fibers derived from the facial nerve (VII) synapse here. - Postganglionic parasympathetic fibers "hitch-a-ride" on branches of V2 into the orbit (within the orbit they then jump onto a branch of V1) where they innervate the lacrimal gland, located in the upper lateral portion of the orbit. These secretomotor fibers cause the lacrimal gland to secrete tears.

CN IX Glossopharyngeal Nerve Ganglions

Within the jugular foramen two swellings appear on the nerve: the superior and inferior ganglia of IX. Superior ganglion is small and contains few, if any, cell bodies *Inferior ganglion contains cell bodies of afferent neurons*

Utricle and Saccule

Within the vestibule of the bony labyrinth. Receptors within the utricle and saccule monitor 1.) *Static equilibrium* (detecting the orientation of the head with respect to the ground when the head is stationary) 2.) *Linear acceleration* (sensing when the body moves in a straight line) - *Uricle*: responds to acceleration in a vertical direction (as in an elevator) - *Saccule* responds to acceleration in a horizontal direction (as when riding a bicycle on a flat road)

Squamous part of temporal bone

Zygomatic process - Articular tubercle Mandibular fossa (part of the temporomandibular joint)

Jugulo-Omohyoid Node

a Large Inferior Deep Cervical Node Lies at the point where Omohyoid muscle crosses Internal Jugular Vein Receives most of the lymph drainage from the Anterior part of the Tongue and Oral Cavity

Jugulodigastric Node

a Large Superior Deep Cervical Node Located where the posterior belly of Digastric crosses the Internal Jugular Vein Receives drainage from Posterior 1/3 of Tongue and the Palatine Tonsil - often enlarged in tonsillitis - often called the tonsillar node

Great Auricular Nerve

a branch of the cervical plexus (spinal nerves *C2 & C3*), supplies facial skin over the angle of the mandible and in the parotid region.

Central Venous Line Placement

a catheter can be inserted into the subclavian vein for the purpose of administering medications, nutrition, or for monitoring venous blood pressure. An infraclavicular approach is taken, in which a needle is inserted horizontally, using the middle portion of the clavicle as a guide to finding the subclavian vein. - Care must be taken to avoid damaging the subclavian artery (passing the needle too far posteriorly) or puncturing the cervical pleura (angling the needle too far inferiorly) (pic is red but it is a VEIN!)

Piriform Recess

a depression on either side of the laryngeal inlet - a location where foreign bodies (steak, hot dogs, etc.) frequently lodge and can obstruct the flow of air!

Carotid Sinus

a dilated region of the proximal part of the internal carotid artery (just distal to the bifurcation). Receptors in the wall of the carotid sinus (baroreceptors) detect changes in blood pressure

LeFort Type I

a fracture through the alveolar process of the maxillae and nasal septum. The upper teeth become detached from the face with the bone fragment.

Ansa Subclavia

a nerve cord that is a connection between the middle and inferior cervical ganglion, and *forms a loop around the subclavian artery* - Communicating branch downwards anteromedial to the vertebral artery makes a loop arournd the subclavian artery from anterior to posterior and then lies medially to the internal thoracic artery respectively

Plica Semilunaris

a reddish semilunar fold which lies on the lateral side of the caruncle

Lacrimal Caruncle

a reddish-yellow elevation near the medial angle.

Artery of the pterygoid canal

a small artery that helps supply the nasopharynx and tympanic cavity

Lacrimal Papilla

a small elevation near the medial angle on each eyelid on whose top is a small opening called the *Lacrimal punctum* that collects tears and carries them into a small canal called the *Lcrimal canaliculus*

Tympanic Cavity (Middle Ear) Anterior Wall

a thin plate of bone here separates the tympanic cavity from the internal carotid artery. Two canals open on the anterior wall, Upper and Lower

Tensor Tympani Innevation

a tiny branch from the mandibular nerve (V3)

Sinus Infection can present with symptoms of...

a toothache (and vice versa!)

Stapedius Innervation

a twig from the facial nerve

Sphenoid Greater wing (paired)

a. Foramen rotundum b. Foramen ovale c. Foramen spinosum d. Sphenoidal emissary foramen (small and inconstant) e. Surfaces: cerebral, temporal, infratemporal, orbital

Lateral Pharyngeal Spaces

adjacent to the lateral surfaces of the pharynx between the pharynx and the muscles of the infratemporal fossa *Boundaries*: skull superiorly and investing fascia on the hyoid inferiorly - Continuous with the retropharyngeal space posteriorly and the submandibular space superiorly

Motor Innervation of the Tongue

all muscles with the exception of palatoglossus are innervated by CN XII

Scalp Loose Connective Tissue

allows movement of the SCALP proper on the calvaria, and also can fill with fluid from injury or infection

Superior Petrosal

along margin of petrous part of temporal bone; joins with the tranverse sinus to form the sigmoid sinus

Extrinsic Tongue Muscles

alter the position of the tongue and originate outside and attach to it. a. Genioglossus b. Hyoglossus c. Styloglossus d. Palatoglossus All are "-glossus" muscles are innervated by CN XII with the exception of palatoglossus (CN X)

Intrinsic Tongue Muscles

alter the shape of the tongue and originate/attach within it. All are innervated by CN XII - Superior and inferior longitudinal - Transverse and vertical

Tympanic Cavity (Middle Ear)

an air-filled space within the *Petrous* portion of the temporal bone Lined with a mucous membrane, which also covers internal surface of tympanic membrane Contains the *Auditory Ossicles* - A narrow space whose long axis is parallel to the plane of the tympanic membrane, considered to be a "BOX" with anterior, posterior, medial, and lateral walls, a roof, and a floor

Semilunar Hiatus

an aperture located inferior to the bulla

Median and 2 Lateral Glosso-Epiglottic Folds

anchored to the root of the tongue anteriorly - *Epiglottic valleculae*: spaces between the median and lateral folds

Sternohyoid (Innervation)

ansa cervicalis (motor part of cervical plexus): C1-3

Posterior Inferior Lateral Nasal Nerves

are NOT direct branches of V2, but instead branch from the greater palatine nerves. They penetrate the lateral wall of the nasal cavity, supplying the territory around the inferior concha

Facial Artery

arises either in common with the lingual artery or just superior to it. It passes deep to the digastric anterior belly and angle of the mandible. It loops to groove and supply the submandibular gland; then hooks around the middle of the inferior border of the mandible to enter the face

Thyroid Cartilage Inferior Horn

articulates with the cricoid cartilage at the cricothyroid joints, which help to adjust the length of the vocal folds

Crico-Arytenoid Joints

articulation with the cricoid laminae

Common Carotid Artery (CCA)

ascends and bifurcates at ~C4 (superior border of the thyroid cartilage) into the Internal Carotid Artery and External Carotid Artery

Posterior Auricular Artery

ascends between the external acoustic meatus and mastoid process. It supplies the adjacent muscles, parotid gland, facial nerve, and structures in the temporal bone, auricle, and SCALP - 2 terminal branches: maxillary & superficial temporal

Cricotracheal Ligament

attaches Cricoid Cartilage to the first Tracheal Ring

Arytenoid Cartilages Muscular Process

attachment of posterior and lateral cricoarytenoid muscles

Arytenoid Cartilage Vocal Process

attachments of the conus elasticus/vocal ligament

Larynx Vestibule

between aditus and vestibular folds

Omoclavicular Posterior Triangle

between omohyoid inferior belly and clavicle Major contents: Subclavian artery, part of the Subclavian vein, Suprascapular artery, Supraclavicular lymph nodes - Supraclavicular fossa is seen in surface anatomy

Larynx Inlet/Audtis

between the aryepiglottic folds

Falx Cerebri

between the cerebral hemispheres Attaches from the crista galli to the internal occipital protuberance

Pretracheal Space

between the infrahyoid muscles and the trachea. It can extend into the anterior mediastinum, where the pretracheal fascia blends with the pericardium

Retropharyngeal Space

between visceral prevertebral and visceral pretracheal fasciae - Movement of the pharynx, esophagus, trachea, and larynx during swallowing

Larynx Infraglottic Cavity

between vocal folds and inferior border of cricoid cartilage

Scalp Dense Connective Tissue

binds skin to the epicranial aponeurosis, ensheaths most of the blood vessels, and contains the nerves supplying the SCALP

Middle meningeal artery

blood supply to the dura (dura is highly vascularized)

Recurrent Laryngeal Nerve in Anterior Triangle

both the left and right nerves pass through the neck, but only the right recurrent laryngeal originates from the vagus in the neck

Hard Palate Mucosa

bound tightly to the bone Surface features: 1.) *Transverse palatine folds (rugae)*: the ridges that run parallel to each other in the most anterior part of the hard palate 2.) *Palatine raphe*: A streak that runs down the midline and is the site of the fusion of the palatine shelves 3.) *Palatine glands*: numerous and the openings give a pitted, orange peel appearance

Superior Laryngeal Nerve

branches off the vagus nerve about the level of the inferior ganglion

Olfactory Nerves

bundles of axons of neurons with cell bodies in the mucous membrane of the nasal cavity - Synapse on Olfactory Bulb of CN I

Posterior Nosebleed (Epistaxis)

can be life threatening. The vessels are larger and not compressible (compared to the more common anterior nosebleeds). Usually associated with coagulopathy and hypertension Treatment involves remedying the underlying condition, compression of the vessels and in some cases, surgical ligation of the offending vessels - Difference between anterior and posterior epistaxis is blood in the pharynx!

Nasal Cavities - Medial and Lateral Walls

cartilaginous, membranous, and bony

LeFort Fractures

caused by trauma to the midface, were classified by Dr. Le Fort, a French surgeon, in the early 1900s. Midface mobility is a sign of Le Fort fracture. Types I: a fracture through the alveolar process of the maxillae and nasal septum Type II: Unilateral or bilateral fracture through the maxillae, infra-orbital foramina, lacrimal bones, and bridge of the nose. This produces a triangular fragment in the central face that is detached from the rest of the skull. Type III: A horizontal fracture through the greater wings of the sphenoid bones, frontozygomatic sutures, superior orbital fissures, and ethmoid bone. This essentially separatesthe facial skeleton from the cranial vault. Fracture of the ethmoid bone can cause leakage of CSF into the nasal cavity (CSF rhinorrhea).

Pharyngeal Tonsil

collection of lymphoid tissue in the roof/posterior wall of the nasopharynx (AKA "adenoids" when enlarged)

Trochlear Nerve (CN IV)

comes off the dorsal part of the midbrain, passes through the cavernous sinus, enters the superior orbital fissure, and passes superomedially to supply the superior oblique muscle.

Cerebral Arterial Circle (Circle of Willis)

communication between the basilar and both internal carotid arteries *Branches*: Anterior, Middle, and Posterior cerebral arteries (ACA, MCA, PCA); Anterior and Posterior Communicating arteries

Gingivae (Gums)

composed of fibrous tissue covered with mucous membrane and are attached firmly to the alveolar processes of the mandible, maxilla and necks of the teeth

Intercavernous Sinuses

connect the cavernous sinuses through the hypophyseal fossa; deep to diaphragma sellae, anterior and posterior to the hypophysis

Thyroid Cartilage Superior Horn

connected superiorly to the hyoid bone via the thyrohyoid membrane

Inferior Ophthalmic Vein

connects to the pterygoid plexus of veins as it passes along the inferior part of the orbit. These lie in the outer part of the infratemporal fossa

Lateral Soft Palate

continuous with the wall of the pharynx and is joined to the tongue and pharynx by the palatoglossal and palatopharyngeal arches, respectively (also known as the pillars of the fauces)

Confluence of Sinuses

convergence of straight, superior sagittal, and inferior sagittal, and occipital sinuses

Salipingopharyngeal Fold

covers the salpingopharyngeus muscle that opens the pharyngotympanic (PT) ( or Eustachian) tube on swallowing

First Arch Neural Crest Cells become...

create the cartilage of the maxillary process and cartilage of the mandibular process (*Meckel's cartilage*). From these cartilages develop the incus & malleus - bones of the middle ear.

Posterior Ethmoidal Sinuses Drain

drain into superior meatus.

Inferior Petrosal

drains cavernous sinus into IJV; also connects to basilar plexus and therefore the internal vertebral plexus

Nasolacrimal orifice of the Nasolacrimal duct

drains the lacrimal sac and opens into the inferior meatus

Opthalmic Nerve (CN V1)

emerges from the trigeminal ganglion goes through the lateral wall of the cavernous sinus and enters the SOF. It usually splits into three branches just before it goes into the fissure

Dural Sinuses

endothelial lined spaces between periosteal and meningeal layers. T Drain blood from cerebral and diplöic veins - Many are located in the dural partitions - May see indentations of the sinuses on the skull (e.g. "groove for sigmoid sinus")

Goiter

enlargement of the gland (not cancer) may be caused by several factors - Hereditary factors may cause goiters. Risk factors for the development of a goiter include female, age over 40 years, inadequate dietary intake of iodine, living in an endemic area, and a family history of goiter.

CN XII in Anterior Triangle

enters submandibular triangle deep to the posterior belly of the digastric

Descending palatine artery

enters the greater palatine canal and divides into greater and lesser palatine arteries, supplying the hard and soft palates, respectively

Oculomotor Nerve (CN III)

enters through the superior orbital fissure and splits into: - Superior ramus which supplies the superior rectus and levator palpebrae superioris muscles and - Inferior ramus which supplies the inferior rectus, medial rectus, and inferior oblique muscles - Also associated with the inferior ramus, located between the optic nerve and the lateral rectus muscle is a parasympathetic ganglion, the *ciliary ganglion*

Abducens Nerve (CN VI)

exits from the pons, enters the cavernous sinus and SOF to the lateral side of the orbit to supply the lateral rectus muscle.

Superior Laryngeal Nerve in Anterior Triangle

external & internal branches (the internal pierces the thyrohyoid membrane with the superior laryngeal artery to enter the larynx)

Hyoid Bone

floating "U shaped" bone located at *C3* Landmark for neck structures, and several cartilages of the larynx. - Body, 2 greater horns, 2 lesser horns, - Suspended from the styloid processes by the Stylohyoid ligaments. - Attaches anterior neck muscles (suprahyoid and infrahyoid), and muscles of the larynx and pharynx

Central Artery of the Retina

follows the Optic Nerve to the region of the disc

Parathyroid Gland Blood Supply and Venous/Lymphatic Drainage

follows the pattern of the thyroid gland

Angular Vein

formed at the medial angle of the eye by the union of the *supra- orbital and supratrochlear veins* - below the nose it becomes the *facial vein*, a tributary of the internal jugular vein. The veins of the face have clinically important connections to venous structures deep to the face (Ophthalmic Veins, Deep Facial Vein, and Pterygoid Venous Plexus)

Tympanic Cavity (Middle Ear) Roof

formed by a thin plate of bone called the *Tegmen Tympani* that separates the tympanic cavity from the meninges and the temporal lobe of the brain

Tympanic Cavity (Middle Ear) Floor

formed by a thin plate of bone that separates the tympanic cavity from the superior bulb of the internal jugular vein

External Jugular Vein (EJV)

formed just below the angle of the mandible just inferior to the auricle by the union of the retromandibular vein (posterior division) & posterior auricular vein - Crosses the outer surface of the SCM in the superficial fascia, just deep to the platysma - Pierces the investing layer of deep fascia at the posterior border of the SCM, then descends to the inferior posterior triangle to join the subclavian vein - Receives the transverse cervical, suprascapular, and anterior jugular veins - Approximate it by drawing a vertical line from the angle of the mandible to the midpoint of the clavicle

Ethmoid Bulla

forms a bulge of bone in the middle meatus

First Arch Mesenchyme from Neural Crest

forms the substrate for facial bones that develop via intramembranous ossification = maxillae, mandible, zygomatic bones, and the squamous part of the temporal bones.

Pterygopalatine Fossa

fossa deep to the infratemporal fossa and between the pterygoid process and maxillary tuberosity

Vestibular Ligament

free inferior margin margin of Quadrangular Membrane Extends between the thyroid and arytenoid cartilages and is protective in function - Vocal fold: mucosa covered vestibular ligament - Rima vestibuli: space between the vestibular folds

Optic Tract

from Chiasma to Thalamus LGN

Hyaline Laryngeal Cartilages (Embryology)

from lateral plate mesoderm of the 4th and 6th arches within the arytenoid swellings

Laryngeal Muscles (Embryology)

from mesenchyme of the *4th and 6th arches* Innervation: Superior Laryngeal (*4th arch*) and Recurrent Laryngeal nerves (*6th arch*)

Epiglottis (Embryology)

from posterior part of the hypobranchial eminence (4th arch) or mesenchyme that migrates into the larynx at a later time

CN IX Glossopharyngeal Nerve Emerges

from the *Medulla* and leaves the cranial cavity through the *Jugular Foramen*

CN 3 Emerges...

from the *anterior surface of the midbrain near its junction with the pons*

Transverse Facial Artery

from the Superficial Temporal Artery Runs parallel and just inferior to the zygomatic arch The "second-most" important artery to the face

Occipitofrontalis muscle

frontal belly (frontalis muscle) and occipital belly (occipitalis muscle)

Mandibular prominences (paired)

give rise to the lower jaw (V3 innervation) - Initially, a cleft exists between the mandibular and maxillary prominences, giving the embryo a wide mouth. This cleft zips shut, reducing the mouth size and relocating the opening of the parotid duct in the oral cavity.

Hard Palate

has a bony skeleton formed by the *palatine processes of the maxillae and the horizontal plates of the palatine bones* - Incisive fossa is a depression in the midline just posterior to the central incisors - Palantine foramen: Medial to the 3rd molars, the greater palatine foramen pierces the palate and just posterior to this is the lesser palatine foramen.

Thyroid Gland

has a median *Isthmus* and 2 *Lateral Lobes* - Each lateral lobe has a superior and an inferior pole *Superior pole* lies lateral to the thyroid cartilage at about *C5* *Inferior pole* lies at about *C7* *Isthmus* connects the two lateral lobes, lying anterior to 2nd and 4th tracheal cartilages - Sometimes a pyramidal lobe lies superior to the isthmus along the thyroid cartilage. This lobe represents the remains of the thyroglossal duct, through which thyroid gland tissue descends during development.

Posterior Surface of the Tongue

has no papillae, but there surface is irregular and bumpy because of the underlying lymphoid nodules. Collectively these nodules are known as the lingual tonsil.

Sigmoid Sinus

in PCF on temporal and occipital bones; continues inferiorly into the internal jugular vein at the jugular foramen

Occipital Sinus

in falx cerebelli; connects to internal vertebral plexus and confluence of sinuses

Falx Cerebelli

in the PCF Separates the cerebellar hemispheres

Frontal Crest

in the anterior cranial fossa)

Inferior Orbital Fissure

in the floor of the orbit Contains the *Maxillary Nerve* and one of its branches, the *Zygomatic nerve*, and *Infraorbital artery and vein*

Infraorbital Groove and Canal

in the floor of the orbit transmits the *Infraorbital nerve and vessels* - these structures reach the face by emerging through the infraorbital foramen

Granular foveae

indentations on inner calvarium from arachnoid granulations

Inferior sagittal Sinus

inferior margin of falx cerebri

Stye (Hordeolum)

inflammatory infection of one or more of the sebaceous glands of the eyelid

Orbital Fascia and Fat

inside of the orbit is lined by orbital fascia (the *periorbita*). The fascia acts as the periosteum of the bones that form the walls of the orbit. The orbital fat lies mostly posterior in the orbit and protects the eyeball and extra-ocular muscles

Middle Ethmoidal Sinuses Drain

into the middle meatus

Maxillary Sinus Drainage

into the posterior part of the hiatus semilunaris in the middle meatus.

Sphenoid Sinuse Drainage

into the spheno-ethmoidal recess

Frontal Sinus Drainage

into through the frontonasal duct into the infundibulum into the semilunar hiatus in the middle meatus.

Bregma

junction of coronal and sagittal sutures

Nasion

junction of frontonasal and internasal sutures

Lambda

junction of lambdoid and sagittal sutures

Tenorial Notch

large gap anteromedially; allows the passage of the brainstem

Larynx Ventricle

lateral recesses between the vestibular and vocal folds - End in blind pouches called saccules

Lower Opening in the Tympanic Cavity (Middle Ear) Anterior Wall

leads into the *Pharyngotympanic Tube*

Postganglionic Fibers to the Head and Neck

leave the superior cervical ganglion as several *Carotid nerves* - these pass onto the internal and external carotid arteries, forming internal and external carotid plexuses. - Postganglionic sympathetic fibers *follow branches of the external carotid artery* (e.g., facial artery, superficial temporal artery) onto the face, and then *hitch rides on cutaneous branches of CN V* to reach and innervate sweat glands (sudomotor fibers), arrector pili muscles (pilomotor fibers), and blood vessels (vasomotor fibers).

Submandibular Space

located below the tongue in the floor of the mouth 2 interconnected parts: one above the mylohyoid muscle (deep part) and one below it (superficial part). Infections may originate in this space from the teeth, salivary glands, or oral cavity and could spread into the thorax. - Communicates with the lateral pharyngeal spaces inferiorly

Superior Sagittal Sinus

located in the superior margin of the falx cerebri

Pterion

located on the lateral skull where four bones join: squamous temporal, greater wing of sphenoid, parietal and frontal bones. Clinically important because it is a thin region of the skull that overlies the anterior branch of the middle meningeal artery. Fracture of the skull here could tear the underlying artery and cause blood to pool between the skull and dura mater = *Epidural hematoma*

Pharyngeal Arch Cartilage Bar

made from neural crest a temporary structure thought to give initial support to the pharyngeal arch - later it is transformed into other structures (often bone, adult cartilage, or ligament)

Thyroglossal Cyst

may lie at any point along the migratory pathway of the thyroid gland but is almost always in the midline of the neck. Most are near the hyoid bone. Some individuals can have a lingual thyroid gland if the gland fails to migrate entirely

Fontanelles

membrane-filled gaps between developing cranial bones of fetuses and newborns A. Anterior fontanelle B. Posterior fontanelle C. Sphenoidal fontanelle D. Mastoid fontanelle

Pharyngeal Arch Neural Crest

migrates from the region of the developing brain = gives rise to skeletal structures and connective tissues

Motor Innervation of Pharynx

mostly from CN X with the exception of CN IX and V3 (see above)

Cervical Cardiac Branches in Anterior Triangle

nerves to the heart arising in the neck

Tubal Tonsil

of lymphoid tissue near the opening of the PT tube

Two Arytenoid Swellings

onvert the primitive glottis into a T-shaped opening that becomes reduced to a narrow slit

Salivary Glands

parotid, submandibular and sublingual glands They are small accessory salivary glands scattered all about the oral cavity. (parotid will be discussed elsewhere.) - Secrete saliva that functions to: o Keeps mucous membranes moist o Lubricate food during mastication o Intitate digestion of starches o Protect against caries o Be necessary for the ability to taste

Frontal Nerve

passes above the levator palpebrae muscle, and divides into supratrochlear and supraorbital nerves near the outer part of the orbit

CN IX in Anterior Triangle

passes b/n the stylopharyngeus and middle constrictor muscles to gain access to the oropharynx and oral cavity

Superior Ophthamic Vein

passes back into the superior orbital fissure to terminate in the cavernous sinus, and is usually joined along the way by the inferior ophthalmic vein, where they collectively pass into the cavernous sinus.

Infratrochlear Nerve

passes below the trochlea to supply a small area of skin on the medial surface of the upper eyelid.

Lingual Artery

passes deep to CN XII and the posterior belly of the digastric to enter the oral cavity deep to the hyoglossus muscle

Nasocoliary Nerve

passes medially between the superior oblique and medial rectus. It gives off anterior and posterior ethmoid branches and ends by becoming the infratrochlear nerve supplies skin in the lower medial part of the eyelid.

Occipital Artery

passes posteriorly, immediately medial and parallel to the posterior belly of the digastric twisting around CN XII

Lacrimal Nerve

passes superolaterally to the lacrimal gland. In the orbit it receives PS fibers from the zygomatic branch of V2. The cell bodies of these fibers lie in the pterygopalatine ganglion and stimulate tear production. The lacrimal nerve also supplies sensation to the upper lateral skin of the eyelid.

Pharyngeal Branches in Anterior Triangle

pharyngeal constrictor and soft palate muscles

Examples of regions/organs whose pathologies may present as enlarged nodes in these "levels"

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Hematoma

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Internal Thoracic Artery

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MRI Straight Sinus and Confluence of Sinuses

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Paratracheal lymph nodes - Pic

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Spokane Pic of Lateral Nasal Wall Cross-Section

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Oropharynx

posterior to the oral cavity - Digestive function - Bounded by the soft palate, base of the tongue, epiglottis and the pillars of the fauces. - Tonsillar bed (the space between the pillars) is formed by the superior pharyngeal constrictor and a thin fibrous sheet of the pharyngobasilar fascia (blends with the periosteum of the cranial base)

Pharyngeal Recess

posterior to the salpingopharyngeal fold (can be a site of carcinoma, so must be visualized completely on endoscopy)

Arachnoid granulations

projections of arachnoid mater that return CSF back into circulation

Maxillary Nerve (V2) and Branches

provides sensation to the posterior portions of the nasal cavity (lateral walls and nasal septum), nasopharynx, maxillary sinus, upper teeth and gingivae, hard and soft palates, orbit, and midface

Pharyngeal artery

reaches nasopharynx through the *palatovaginal/pharyngeal canal*

Parathyroid Glands

reddish-brown structures, usually 4 in number, which lie in the capsule on the posterior surface of the thyroid gland - in rare cases may be located within thyroid glands - more often there are multiple PT glands (6-8) *Secrete parathyroid hormone* 1.) Increases blood Ca levels - Stimulates osteoclasts to break down bone and release Ca - Increases GI Ca absorption 2.) Antagonist to Calcitonin

Premaxilla

region of the maxilla anterior to the *Incisive foramen*

First Arch Aortic Arch Artery

regresses as the first pharyngeal arch develops. It probably only contributes to a small portion of the definitive *maxillary artery*

Foramen Cecum

remnant of the thyroglossal duct - frequently absent

Basilar Artery

runs along the clivus on the pons; formed by the two vertebral arteries that enter through the foramen magnum

Lacrimal Artery

runs along the lateral wall of the orbit

Transverse Sinus

runs anteriorly along the occipital bone

Superior Thyroid Artery

runs deep to the infrahyoid muscles and ends at the thyroid gland. It gives rise to the *superior laryngeal artery* (supplies the larynx).

CN IX Tonsilar Branches

sensory to mucosa of the fauces and palatine tonsils

Greater and Lesser Palantine Nerves

sensory to the hard and soft palates, respectively

Nasal Pits

separate the medial and lateral nasal prominences

Tentorium Cerebelli

separates the PCF from the MCF and forms a roof over the cerebellar hemispheres Attaches to the clinoid processes, petrous ridge of the temporal bone, and the occipital bone - Tentorial Notch

Epidural Hematoma

serious condition from tearing branches of the *middle meningeal artery*, creating a biconvex lens-shaped (football!) hematoma. Blood tears Dura off the skull, but does not spread past sutures. If blood is not evacuated from the epidural space, then severe damage to the cerebrum, or death, may occur.

Carotid Body

small organ (like a tiny berry) located in the crotch of the bifurcating common carotid artery. Chemoreceptors in the carotid body detect changes in blood levels of O2, CO2, as well as pH levels.

Croniculate Cartilage

small paired, pyramidal-shaped with an apex, attaching to the aryepiglottic fold

Conjunctival Sac

space behind the eyelids lined by the conjunctiva - Upper and Lower limits are called Superior and Inferior Fornices - Behind eyelids is a *Subtarsal Sulcus* in which foreign particles can become trapped

Occipitofrontalis Innervation

supplied by the *Temporal branch of CN VII*

Carotid Branch

supplies the carotid sinus and carotid body

CN III Skeletal Motor Component Superior Division

supplies the levator palpebrae superioris and the superior rectus muscles

CN III Skeletal Motor Component Inferior Division

supplies the medial rectus, inferior rectus, and inferior oblique muscles

Anterior Ethmoid

supplying sensation to the middle and anterior ethmoid sinuses. This nerve enters the nasal cavity through a small bony slit located along the sides of the crista galli. In the nasal cavity it divides into internal nasal and external nasal branches.

Posterior Ethmoid

supplying sensation to the posterior ethmoid and sphenoidal sinuses.

Ciliary Arteries

supplying the globe

CN IX Lingual Branches

taste and general sensation to posterior 1/3 of tongue

PPF: Communications With Other Regions of the Head *Anterior*

the *Inferior Orbital Fissure* opens into the orbit

First fibers to go when CN III is Compromised are...

the *Parasympathetics* - so you will see a dilated ("blown out") pupil before you see motor signs (palsy)

Face

the anterior aspect of the head - located anterior to the auricles, superior to the margin of the mandible, and inferior to the "hairline". The term is derived from the Latin facies (= countenance), which refers to the appearance of the face. Certain diseases alter the appearance in distinctive ways (e.g., Parkinson's disease).

Subclavian Vein

the direct continuation of the axillary vein at 1st rib. Separated from the subclavian artery by the anterior scalene muscle Behind the sternoclavicular joint it joins the Internal Jugular Vein to form the *Brachiocephalic Vein*

Supraorbital Notch/Foramen

the exit point for the *supraorbital nerve and vessels*

Scalenus Medius

the largest of the 3 Inserts on first rib Gap between the anterior and middle scalenes is traversed by the brachial plexus and the subclavian artery.

Sphenopalatine artery

the medial continuation of the maxillary artery, it enters the lateral wall of the nasal cavity through the sphenopalatine foramen - Serious hemorrhage in the nasal cavity results from damage to this artery

Buccopharyngeal fascia

the posterior and superior-most part of the visceral layer of the Pretracheal Fascia surrounding the superior pharynx and esophagus

Conjunctiva

the sclera on the anterior side of the eyeball ("whites")

Fauces

the space between the oral cavity and the pharynx Boundaries: 1. Superiorly - soft palate 2. Inferiorly - roof of the tongue 3. Laterally - pillars of the fauces (palatoglossal and palatopharyngeal arches)

Venous tributaries of pterygoid plexus

the veins that drain essentially the same regions supplied by the 3rd part of the maxillary artery flow into the pterygoid plexus - Maxillary vein(s) drain the pterygoid plexus

CN IX Pharyngeal Branches

these become part of the pharyngeal plexus of nerves. Pharyngeal branches of IX are sensory to the mucous membranes of the oropharynx, nasopharynx, and pharyngotympanic (auditory) tube.

Posterior Superior Lateral Nasal Nerves

these pass from the PPG through the sphenopalatine foramen to supply sensation to the upper portion of the lateral nasal wall - i.e., the mucosa of the superior and middle conchae

Alar Fascia

thin delicate fascia that crosses the retropharyngeal space. It attaches to the buccopharyngeal fascia from the skull to C7, extending laterally to blend with the carotid sheath

Ultimobranchial body

thought to be derived from the Ventral process of the 4th pharyngeal pouch [some claim it to be from a 5th pouch (because ultimo translates to "the last")]. Regardless of its classification - the endoderm of the ultimobranchial body migrates into the developing *thyroid gland to form its parafollicular cells (C-cells)*. These cells produced the hormone *calcitonin*

Carotid Branches in Anterior Triangle

tiny; form plexus with branches of IX. They are afferent nerves supplying the carotid sinus and carotid body, carrying chemical and pressure information

Lateral Nasal Artery

to the ala of the nose

Dorsal Nasal Artery

to the external nose

Palpebral Artery

to the eyelid

Supraorbital Artery

to the forehead and anterior scalp

Supratrochelar Artery

to the forehead and scalp

Inferior and Superior Labial Arteries

to the lower and upper lips, respectively. The superior labial artery also supplies blood to the anterior part of the nasal septum

Anterior and Posterior Ethmoidal Arteries

to the paranasal sinuses as well as nasal septum and lateral nasal wall.

First Arch Cranial Nerve

trigeminal nerve (CN V) - but only its maxillary and mandibular divisions (V2 and V3)

Parapharyngeal Space

two lateral pharyngeal spaces + retropharyngeal space

Craniometric Points

used radiographically in medicine and in anthropology to make measurements of the head and skull for descriptive and comparative purposes. - Nasion = junction of frontonasal and internasal sutures - Bregma = junction of coronal and sagittal sutures - Lambda = junction of lambdoid and sagittal sutures - Pterion = located on the lateral skull where four bones join: squamous temporal, greater wing of sphenoid, parietal and frontal bones.

Ganglionic Branches of V2

usually 2 in number, they suspend the pterygopalatine ganglion from V2 - *Sensory nerve fibers from the palate, nasopharynx, and nasal cavities* access V2 via the ganglionic branches - Also, *postganglionic parasympathetic and sympathetic nerve fibers* leave the pterygopalatine ganglion and join V2 through the ganglionic branches.

Frontal Sinus

usually paired, but rarely the same size. See the hemi-skull