Neck

5 branches of parotid gland

"To Zanzibar by Motor Car" Temporal, Zygomatic, Buccal, Marginal mandibular, Cervical

Course of the branches from cervical plexus: MOTOR

(!) C1 with hypoglossus to geniohyoid & thyrohyoid, (2) Ansa cervicalis (C1-3) to sternohyoid, omnohyoid, sternohyoid. (3) Phrenic n on anterior scalene betw subclavian a & v to diaphragm (Sensory and motor)

"Near Triad" "Accommodation Reflex"

(1) Accommodation of lens (para from CNIII), (2) Convergence of eyes (CNIII), (3) constriction of pupil (para) by CNIII

CN V1- Opthalmic: branches:

(1) Frontal nerve, (2) Nasociliary nerve, (3) Lacrimal nerve, (4) Recurrent meningeal n

Lymphatic Drainage of the face

(1) Parotid, (2) Submandibular, (3) Submental. All drain into deep cervical nodes along internal jugular vein

Sternocleidomastoid

(Accessory n, & C2 to C3): Manubrium sterni and medial clavicle Mastoid process and superior nuchal line Tilt head on the same side, rotate face towards the opposite side, together draw head forward

Sternocleidomastoid

(Accessory n, & C2 to C3): Manubrium sterni and medial clavicle Mastoid process and superior nuchal line Tilt head on the same side, rotate face towards the opposite side, together draw head forward!!!!!!!!!!!!!!!!!

Trapezius

(Accessory n, & C3 to C4): Superior nuchal line, external occipital protuberance, lig. nuchae, spines of C7-T12 Lateral one-third of clavicle, acromion, scapular spine

Sternohyoid

(C1 to C3 via ansa cerv.): Sternoclavicular joint, inside Body of hyoid Depresses hyoid

Omohyoid

(C1 to C3 via ansa cerv.): Sup.border of scapula, medial to scapular notch Body of hyoid Depresses hyoid

Levator scapulae

(Dorsal scapular nerve) Transverse processes of C1-C4 Upper medial border of scapula Elevates scapula

Splenius capitis

(Post rami of middle cervical nerves): Mastoid process, superior nuchal line Lower half of lig. nuchae, spines of C7-T4 Rotate face towards the same side; ogether draw head backwards

Rectus Capitis anterior

(ant. rami of C1-C2) Anterolateral surface of atlas Basilar part of occipital bone Flexes head

Rectus Capitis lateralis

(ant. rami of C1-C2) Transverse process of atlas Jugular process of occipital bone Flexes head laterally to the same side

Longus Colli

(ant. rami of C1-C3)Flexes neck anteriorly and laterally, slight rotation to the opposite side Superior oblique part Transverse processes of C3-C5 Tubercle of anterior arch of atlas Inferior oblique part Transverse processes of C5-C6 Ant. surface of vertebral bodies of T1-T3 Vertical part Ant. surface of vertebral bodies of C2-C4 Ant. surface of vertebral bodies of C5-T3

Longus capitis

(ant. rami of C2-C6) Transverse processes of C3-C4 Basilar part of occipital bone Flexes head

Middle scalene

(ant. rami of C3-C7) Transverse processes of C2-C7 Upper surface of rib 1 Elevates rib 1

Middle scalene

(ant. rami of C3-C7) Upper surface of rib 1 Elevates rib 1

Anterior scalene

(ant. rami of C4-C7) Transverse processes of C3-C6 Upper surface of rib 1 Elevates rib 1

Anterior scalene

(ant. rami of C4-C7) Upper surface of rib 1 Elevates rib 1

Posterior scalene

(ant. rami of C5-C7) Upper surface of rib 2 Elevates rib 2

Rectus capitis anterior and lateralis

(anterior rami C1-2)

External carotid branches: Facial

(branches: tonsillar, ascending palatine) From the anterior surface of carotid Deep to stylohyoid and digastric Turns over the edge of the mandible

Longus colli

(flexes neck anteriorly= C1-3)

5. Dorsal scapular

(replacing deep branch of transverse cervical) Not always present From 3rd part Along the medial border of scapula

Cervicothoracic or "Stellate" (C8 - T1)

-star shaped

CN V2- Maxillary: main branches

1) zygomatic n, (2) infraorbital n, (3) nasal n, (4) Palatine n, (5) Meningeal branch

Symptoms of Horner's syndrome

1. flushing of the face (loss of vascular tone) 2. ptosis (paralysis if superior tarsal muscle) 3. anhydrosis (from denervation of sweat glands) 4. miosis (unopposed constrictor pupillae)

External carotid branches: Occipital

5.Occipital (loops around CN loops around CN12) From the posterior surface of carotid At the level of facial a. Deep to the digastric Supplies posterior scalp *descending branch anastomoses with deep cervical artery off costocervical trunk

Fascial spaces and spread of infections: Retropharyngeal space part II

: infections between the alar/buccopharyngeal fascia and preverterbral layer (posterior layer of prevertebral fascia; "retropharyngeal abscess"), can extend inferiorly to the diaphragm; air from a ruptured airway/esophagus can result in a pneumomediastinum via this fascial space

Name the branches- angiogram

A- common carotid, B- superiorthyroid, c- lingual, d- facial, e- ascending palantine, f- ext carotid, g- occipital

CN VI

Abducens

CN XI

Accessory

Name the branches

Angiogram of the head: 1. Common Carotid Artery. 2. Internal Carotid Artery. 3. Ascending pharyngeal Artery. 4. Occipital Artery. 5. Superficial Temporal Artery. 8. Middle meningeal Artery. 9. Maxillary artery. 10. Facial artery. 11. Lingual artery. 12. External carotid artery. 13. Superior thyroid artery

Innervation of omohyoid, sternohyoid and sternothyroid

Ansa cervicalis

Innervation of digastric

Anterior belly = CN V Posterior belly = CN VII

Supraclavicular branches C3-4

Anterior, middle, and posterior. Descend to supply skin over clavicle and shoulder

Tongue pointing to P's left side

Atrophy in tongue muscle => something wrong with left 12, then deviation of tongue, pushes tongue toward affected side. Tongue deviates toward affected side -> points to left, says it's a left CN XII palsy

Branch of CN V that carries parasympathetics to parotid

Auriculotemporal

Major nerve to TMJ (pain)

Auriculotemporal

External ear: External Auditory Meatus: Innervation:

Auriculotemporal n. (CN V3)(majority), CN VII, CN IX, Auricular branch CN X (mainly tympanic membrane)

Describe the expected findings of physical examination of a 65-year-old female with a CN III palsy resulting from an aneurysm in the superior cerebellar artery. Compare and contrast these findings to those from a 49-year-old female with a CN III palsy resulting from poorly controlled diabetes

Bc nerve is on outside- parasympathetic branches go to pupillae constrictor- effected in compression, Loss of pupillary reflex in first, not necessarily the other components. When get to diabetic patient, wouldn't necessariliy see pupillary reflex but would see inferior rectus, superior rectus motor would be affected. Go back to CN iii . Compressing nerve like aneurysm- initially affects parasympathetic fibers. If keeps going, then affect other motor fibers which are down center (eg superior rectus) along with vessels in diabetic

Brachial plexus

Between the anterior and middle scalene Upper, middle and lower trunks Dorsal scapular nerve: rhomboid muscles Long thoracic nerve: serratus anterior Suprascapular nerve: supraspinatus and infraspinatus

42. Accommodation involves what three actions? By what cranial nerve(s) are they mediated?

Bilateral contraction of the medial rectus (GSE) Constriction of the pupil by constrictor pupillae (GVE) Contraction of the ciliary muscle (GVE) **all innervated by CN III

Brachial plexus branches at the neck

Brachial plexus passes between anterior and middle scalene with the subclavian artery in the scalene triangle. **superior, middle, and inferior trunks** Dorsal scapular (C5): rhomboids, levator scapulae Long thoracic (C5,6,7): serratus anterior, Suprascapular (C5, C6): supraspinatus, infraspinatus

Structures that course between anterior and middle scalene

Brachial plexus, subclavian artery

8. Where is the "danger triangle" of the face? Why is it significant?

Bridge of the nose down to the bottom of the upper lip There are venous connections from the face to the cranial cavity (valveless) with the potential to spread infection to the brain. Facial v. branches (deep facial, superior and inferior ophthalmic) go to the pterygoid plexus of veins and cavernous sinus. Can cause thrombophlebitis

3. What is the significance of "bridging veins"? What condition is associated with tearing of these vessels?

Bridging cerebral veins between arachnoid and dura mater can tear in subdural hemorrhages - banana (Blood from brain to superior sagittal hematoma), looks like a crescent, shaken baby syndomre/elderly (brains atrophy as you age)

Which branches of CN VII most closely associated with parotid duct?

Buccal

25. Identify the cranial nerve which innervates both the inside and the outside of the cheek.

Buccal n. (CN V3)

Innervation to buccal (cheek) mucosa:

Buccal n. (CN V3)

Sternohyoid

C1 to C3 via ansa cerv.) Manubrium, inside Lamina of thyroid cartilage, oblique line Depresses larynx

Mm. innervated by C1

C1 via CN 12: geniohyoid, thyrohyoid

Left eye that is illuminating is constricting, but on right side, no direct response.

CN III on right side => right CN III palsy

Severe ptosis on left side, when lift eyelid, see dilated pupil, lateral deviation

CN III, lesion on left

Parasympathetics are carried by _________

CN III. VII, IX, X. CNIII, VII, IX are involved in "hitch hiking" on CN V

Sensory of tongue (posterior 1/3)

CN IX (GVA, SVA). small patch which is CN X, internal laryngeal n. GVA: gen. Sense, SVA: taste

Afferent - efferent limbs of gag reflex

CN IX - CN X

Which cranial nerve innervates stylopharyngeus, carotid sinus, and pharynx (sensory)

CN IX Glossopharyngeal nerve

Innervation of carotid sinus and carotid body

CN IX, CN X

List the nerves most at risk of injury from carotid endarterctromy?

CN IX- dysphagia, CN X- dysphagia, hoarsness, CN XI- weakness with shoulder elevation, turning head to contralateral side. CN XII- tongue weakness, deviates towards weakness. Ansa cervialis + C1 to thyrohyoid = dysphagia. Sympathetic trunk- Horner syndrome

Major cutaneous nerve of face

CN V

Major sensory nerve (GSA) of the head

CN V

Sensory of tongue (anterior 2/3)

CN V3, lingual n (GSA). CN VII, chorda tympani via lingual n. (SVA). => Taste carried by chorda typani, hitchhike on lingual n

4. What nerves provide the major sensory innervation (GSA) to the cranial dura mater?

CN V: Meningeal branches of ethmoidal nerves (V1-ACF), meningeal of V2 (MCF), mandibular of V3 (MCF) and meningeal of C1-3 and vagus (PCF), V1 for falx and tentorium

Innervation of the "intra" and Extraocular muscles

CN VI- Abducens (Lateral rectus), CN IV- Trochlear (Superior Oblique), CN III Oculomotor (ext m except superior obliue, lateral rectus, sphincter pupillae, ciliary m)

Parotid gland relationships:

CN VII ECA, retromandibular vein Mandible, masseter, buccinator (duct)

12. List the important structures which course through the parotid gland. What nerve provides GSA sensory innervation to the connective tissue capsule of the parotid?

CN VII and TZBMC branches, external carotid artery, retromandibular vein and tributaries, masseter, styloid process and the mandible.

Chief structures that traverse internal acoustic meatus

CN VII and VIII

Afferent - efferent limbs of cough reflex

CN X - CN X

Which cranial nerves carry hitch-hikers from the cervical plexus?

CN XI and XII

Motor of tongue

CN XII Hypoglossal n. (GSE). Palatoglossus m (CN X)

33. A patient protrudes his tongue and it deviates to the right. Identify the nerve and the general site of the lesion.

CN XII injury on the right

Which cranial nerves hitchhike on CN V?

CNIII, VII, IX

Uvula deviates towards the right and pillar arches are sagging on left side. What nerve is injured?

CNX on LEFT lesion=> pillars sag=> cause uvula to deviate contralaterally

Vertebral level of hyoid bone

CV3

Vertebral level of thyroid cartilage

CV4, 5

Vertebral level of cricoid cartilage

CV6

30. Identify three major areas to which venous blood of the nasal cavity drains.

Cavernous sinus, pterygoid plexus in intratemporal fossa and facial vein

What are the levels of the cervical sympathetic chain?

Cervical sympathetic ganglia are fused: Superior Cervical (C1 - 4) Middle Cervical (C5 - 6) Inferior Cervical (C7 - 8) and occasionally Cervicothoracic or "Stellate" (C8 - T1)

Nerve that provides taste to anterior 2/3 of tongue

Chorda tympani

Specific nerve that elicits secretion from submandibular gland

Chorda tympani

Autonomic ganglia for CN III

Ciliary

Cranial Nerve AUTONOMIC Ganglia

Ciliary ggl Otic ggl. Pterygopalatine ggl Submandibular ggl

Muscle that increases tension on vocal cords

Cricothyroid

16. Identify two antagonistic muscles working at the cricothyroid joint.

Cricothyroid: increases tension on the vocal cords (external laryngeal) Thyroarytenoid: decreases tension on the vocal cords (recurrent laryngeal) Posterior cricoarytenoid: abduct the vocal cords and open the rima glottis Lateral cricoarytenoid: adduct the vocal cords and close the rima glottis

superior cervical ganglion

Damage to the SCG, part of this system, often results in Horner's syndrome. Damage to the T1-T3 regions of the spinal cord is responsible for drooping of the eyelids (ptosis), constriction of the pupil (miosis),

Difference between aneurysm and diabetes

Diabetes- sparing of pupillary reflex bcanatomical arrangement of the nerve fibers in the oculomotor nerve; fibers controlling the pupillary function are superficial and spared from ischemic injuries typical of diabetes. ANEURYSM- compress oculomotor affects Superficial fibers, manifests as third nerve palsy with loss of the pupillary reflex (in fact, this third nerve finding is considered to represent an aneurysm—until proven otherwise—and should be investigated).

Brachial plexus at neck

Dorsal scapular (C5): rhomboids & levator scapulae. Long thoracic (C5,6,7): serratus anterior. Suprascapular (C5,6): supraspinatus, infraspinatus

35. Identify the route by which sublingual nitroglycerin reaches the heart.

Drugs dissolve and enter the sublingual veins that quickly drain into the IJV, brachiocephalic vein and into the right atrium

ct orbits

Ethmoid air cells- black ink blob

26. The superior and middle nasal conchae are part of which bone?

Ethmoid bone

9. Identify the course and branches of CN VII after it exits the stylomastoid foramen.

Exits the base of the skull through the stylomastoid foramen and passes deep to the parotid gland giving 5 branches: Temporal, zygomatic, buccal, marginal mandibular, and cervical nerves. It will also give off a GSA branch to innervate most of the external ear.

18. What cranial nerve innervates the skeletal muscle of the larynx? List specific branches and muscles innervated?

External branch of superior laryngeal nerve: cricothyroid m. and inferior pharyngeal constrictor Recurrent laryngeal nerve: thyroarytenoid m., transverse and oblique arytenoid ms., posterior and lateral cricoarytenoid ms., and thyroepiglotticus m.

Innervation of cricothyroid

External laryngeal nerve

Vascular support of middle ear: Lymphatic drainage

External meatus- mastoid [otitis externa]. Middle ear- parotid, jugulodigastric [otitis media]. Auditory tube-retropharyngeal

CN VII

Facial

7. Identify the 4 major arteries which contribute to the circulation of the face.

Facial, superficial temporal- gives off a transverse facial artery that connects both sides, maxillary, and ophthalmic (internal carotid) arteries, submandibular

External carotid branches: Lingual (to tongue)

From the anterior surface of carotid At the level of hyoid Deep to hypoglossal n. (CN 12) Between middle constrictor and hyoglossus

External carotid branches: . Superior thyroid

From the anterior surface of carotid Reaches the sup. pole of thyroid Gives superior laryngeal artery *anterior branches anastomoses with anterior branch of opposite side* *posterior branch anastomoses with inferior thyroid artery*

External carotid branches: Ascending pharyngeal

From the posterior surface of carotid Between the internal carotid and pharynx

28. Identify the paranasal sinuses which open into the middle meatus.

Frontal sinus (via frontonasal duct), anterior and middle ethmoidal air cells

34. Identify the nerves which supply SVA axons to the tongue. GSA axons. GVA axons. GSE/SVE?

GSE/SVE: CN XII GSA: lingual n. from CN V3 (anterior 2/3) and CN IX posterior 1/3 GVA: CN IX, CN X in the very very back SVA: anterior 2/3 is chorda tympani from CN VII and posterior 1/3 is CN IX, CNX in the very very back

Retropharyngeal abscess

Gas-forming retropharyngeal abscess secondary to fish bone foreign body

Sensory ganglia for CN VII

Geniculate

Site of cell bodies for nerve that carries taste to anterior 2/3 of tongue

Geniculate ganglion

C1 via CNXII

Geniohyoid, Thyrohyoid

CN IX

Glossopharyngeal

Lateral lower lip lymphatic drainage

Goes into submandibular nodes!!!!

Middle cervical ggl: (C5-6)

Gray Rami Middle cardiac nerves Ansa subclavia

Inferior cervical ggl (C7-8):

Gray Rami Vertebral plexus Inferior cardiac nerves Ansa subclavia *Occasionally,

23. Identify two specific branches of CN VII that carry GVE - P axons and hitchhike on CN V.

Greater petrosal n. hitchhikes on CN V1 (lacrimal) and CN V2 (Zygomatic branch) to the glands in the nasal cavity (nasal branches), paranasal sinuses and lacrimal gland. Chorda tympani hitchhikes on CN V3 (lingual) to innervate glands in the oral cavity inferior to the palate.

Ramsay Hunt syndrome

Herpes zoster in geniculate affecting VII, also gives vesicular eruptions where VII innervates external ear.

Superior cervical ggl provides ALL post gang sympathetics to head. Injury to this is _______

Horner's syndrome

51. What are the signs of injury of the cervical sympathetic chain and what is this condition called?

Horner's syndrome: flushing, ptosis, anhydrosis, and miosis injury to the superior cervical ganglion

CN XII

Hypoglossal

Which nerve does tympanic nerve come off of?

IX

Pillar sag on left side

If also add: Headachces, papilledema, weakness, diminished tasete sensation in dry mouth= elevating left shoulder (accessory- 11), diminished taste/dry mouth- 9, where 9,10, 11, in jugular foramen

Reflexes: (In by/Out by): Jaw-jerk

In by CN V (mesencephalic nuc.), Out by CN V

Reflexes: (In by/Out by): Tearing

In by CN V[trigeminal ganglion], Out by CN VII

Reflexes: (In by/Out by): Pupillary

In by retina, CN II, Out by: CN III

Reflexes: (In by/Out by): Blink to startle

In by retina, CN II, Out by: CN VII

Innervation to Parotid region

Inferior angle of mandible- great auricular n (C2,3). Auriculotemporal n- CN V3

43. What nerve(s) innervate the inside of the tympanic membrane? Outside?

Inside: tympanic branch of CN IX Outside: ¾ by auriculotemporal from CN V3 and ¼ by CN X

Papilledema

Intercranial pressure => bulging optic disc region=> pressure on vessels supporting retina

Superior cervical gg (C1-4l: all postganglionic sympathetics to HEAD)

Internal Carotid Nerve External Carotid Nerve Laryngopharyngeal branches Gray Rami Superior cardiac nerves

Sensory nerve to larynx superior to vocal cords

Internal laryngeal

Structures that pierce thyrohyoid membrane

Internal laryngeal nerve, superior laryngeal artery

39. Identify the cranial nerve(s) and muscle(s) used to abduct the eye.

Lateral rectus m. (CN VI), superior oblique m. (CN IV), and inferior oblique m. (CN III)

15. Paralysis of the right levator palatini muscle results in deviation of the uvula to which side?

Left

If eyes at different levels => double vision (DIPLOPIA). Complaints: tripping/falling down stairs. If walk down incline

Left CN IV lesion. Normally, superior oblique is down and out. If can't move eyes down and out, like walking down steps

Patient can't abduct left eye

Left CN VI deviation

When he looks to his left, but left eye will not look left

Left VI

Dilated pupil (mydriasis) on right caused by

Lesion of CNIII

Course of the branches from cervical plexus (cutaneous- all pierce investing fasia at Erb's point)

Lesser occipital (C2): post border of SCM to neck & scalp behind ear Greater auricular (C2-3)- on SCM to base of ear to supply ear, parotid, mastoid region Transverse Cervical (C2-3): horiz to SCM to supply anterolateral neck Supraclavicular (C3-4) anterior, middle and posterior branches down to supply skin over clavicle and shoulder

Which muscle could be affected from cavernous sinus Infection that goes untreated? A. Levator palpebrae superiorus B. Orbicularis oculi C. Orbicularis oris D. Masseter E. Buccinator

Levator palpebrae superiorus - CNIII

Thyroidectomy...what nerves/vessels are in danger? Result?

Ligation of superior thyroid artery (inferior to the origin of the superior laryngeal artery) endangers the external laryngeal nerve Superior thyroid artery external laryngeal nerve Ligation of inferior thyroid artery endangers the recurrent laryngeal nerve Inferior thyroid artery recurrent laryngeal nerve **hoarseness**

Branch of CN V that carries parasympathetic to submandibular

Lingual

37. What structure crosses the submandibular duct twice?

Lingual n.

Testing inferior rectus

Look laterally and DOWNWARD

Testing Superior Oblique

Look medially and DOWNWARD

Testing Inferior Oblique

Look medially and UPWARD

41. How do you clinically test the inferior oblique muscle?

Look medially then look up

21. Identify the muscles of mastication that close the mandible.

Masseter, temporalis, and medial pterygoid muscles

Cn V2

Maxillary

Major artery to internal structures of head

Maxillary

24. The lingual and inferior alveolar nerves pass between which two muscles?

Medial and lateral pterygoid

22. Identify the muscles which are responsible for side to side movements of the mandible.

Medial and lateral pterygoid muscles

31. Identify the major nerves which supply branches to the nasal mucosa.

Medial nasal branch from the anterior ethmoidal and nasopalatine nerves Greater petrosal nerve from the facial nerve, olfactory nerve, nasociliary from anterior ethmoidal, nasal branches from maxillary nerve, nasopalatine on septum, posterior lateral nasal branches, infraorbital (ant sup alv, mid sup alv)

CN V3- runs through foramen ovale. Main branches:

Meningeal branch, lingual n, inferior alveolar n, auriculotemperal n, buccal n (sensory), motor branch or masticatory m and for tensor tympani & tensor veli palatine, sensory brances for external ear

Major arterial supply to calvaria and supratentorial dura

Middle meningeal

2. What vessel provides the major arterial supply to the dura of the middle cranial fossa? What condition is associated with rupture/laceration of this vessel?

Middle meningeal artery from the maxillary artery (through foramen spinosum) Fracture of the pterion, which will cause laceration of the middle meningeal artery causing an epidural hematoma (lemon), contained by the dura

Compartments of the neck:

Muscular: surrounded by the investing Vertebral: enclosed by the prevertebral Vascular: enclosed by carotid sheath Visceral: enclosed by pretracheal

Mm. innervated by CN V-3 (mandibular)

Mylohyoid, anterior belly of digastric

Corneal reflex

Nasociliary of v1 is the in (afferent). Efferent is facial (CNVII)

When you hurt your cornea...

Nasociliary transmits pain signal. Cell bodies of sensory are housed: Trigeminal ganglia (seminlunar) Gasserian

Sensory nerves off V1

Nasociliary, Frontal, Lacrimal: all branches off V1- ophthalmic division of trigeminal

Cervical plexus- motor branches- ansa cervicalis

Nerves C1-C3 form a loop Superior loop from C1 joins the hypoglossal nerve Superior loop innervates the superior belly of omohyoid, upper parts of sternohyoid and sternothyroid Inferior loop from C2-3 innervates the inferior belly of omohyoid, lower parts of sternohyoid and sternothyroid.

Ice cream cone sign

Normal relationship of malleus and incus

Cervical plexus- motor branches- phrenic nerve

ON ANTERIOR SCALENE MUSCLES, covered by prevertebral layer, passes betw subclavian v & a & enters thorax. Provides sensory & motor innervation of diaphragm

CN III

Oculomotor

CN I

Olfactory

What nerves are extensions of the brain?

Olfactory and Optic

Sensory areas supplied by TRIGEMINAL- class

Opthalmic nerve, Maxillary nerve, Mandibular nerve

CN V1

Opthalmic- runs through orbital fissure

CN II

Optic

Branches of maxillary nerve (V2) -- purely sensory, from trigeminal ganglion

Orbital branches Zygomatic nerve Pharyngeal nerve Infraorbital nerve Posterior superior alveolar n. Nasal nerves Greater & lesser palatine nn.

46. Define the terms otosclerosis and hyperacusis.

Osteosclerosis: abnormal hardening of bone and elevation of bone density which can cause conductive hearing loss Hyperacusis: paralysis of the stapedius m. (CN VII injury) resulting in increased perception of loudness

38. Describe the route of sympathetic and parasympathetic innervation to the submandibular and sublingual salivary glands.

Parasympathic: chorda tympani from CN VII (synapse in submandibular ganglion) Sympathetic: postganglionic fibers from superior cervical ganglion give external carotid branches that form a plexus on the facial artery and accompany its branches to the submandibular/sublingual glands Parasympathetics to the submandibular and sublingual glands are carried by the chorda tympani. The facial nerve, CN VII, exits the skull via the internal acoustic meatus. The chorda tympani branches off and travels over the tympanic membrane and exits through the petrotympanic fissure, where it meets up with the lingual nerve. It synapses in the submandibular ganglion to become post-synaptic parasympathetic fibers. It then exits the ganglion and gives parasympathetic innervation to the submandibular and sublingual glands. Sympathetics: starts at T1-T4, synapses in superior cervical ganglion, send branches to the external carotid artery, then sends off branches from the external carotid artery that follow the lingual artery into the mouth

27. Identify the 3 components of the nasal septum.

Perpendicular plate ethmoid, vomer, and nasal septal cartilage Vomer bone inferiorly, septal cartilage anteriorly, perpendicular plate of ethmoid bone postero-superiorly

Structures running together?

Phrenic with ascending cervical Recurrent laryngeal nerve with inferior thyroid artery and trachea internal laryngeal nerve with Superior laryngeal artery (through thyrohyoid membrane) external laryngeal nerve with superior thyroid artery. Vagus nerve behind ICA and IJV (carotid sheath) Glossopharyngeal runs between ICA and IJV before curving around stylopharyngeus. Hypoglossal nerve runs between ICA and IJV. Hypoglossal nerve loops around occipital artery C1 with CN 12. Transverse cervical nerve with facial nerve (superficial cervical ansa)

Site of aspirated lodged fishbone

Piriform recess

17. What muscle functions to abduct the true vocal folds? Innervation?

Posterior cricoarytenoid, recurrent branch of CN X

Posterior Scalene

Posterior scalene (rami of C5-C7) Transverse processes of C4-C6 Upper surface of rib 2 Elevates rib 2

PSNS to parotid gland from CN IX

Postganglionic hitchhikes with auriculotemporal nerve

Spaces

Pretracheal- betw investing & pretracheal extending to mediastinum Retropharyngeal: between buccopharyngeal & alar extending to carina

Contents of ITF include:

Pterygoid muscles CN V3 and branches Branches from CN V2/ CN VII/ CN IX Maxillary artery and branches (sphenomandibular ligament) Pterygoid venous plexus

Subclavian branches:

RIGHT SUBCLAVIAN: brachiocephalic trunk, LEFT SUBCLAVIAN: aorta

Innervation of laryngeal muscles exclusive of cricothyroid

Recurrent laryngeal

Nerve injury that causes hoarseness following thyroid surgery

Recurrent laryngeal

Sensory nerve to larynx inferior to vocal cords

Recurrent laryngeal

19. What nerve(s) innervate(s) the mucosa of the larynx?

Recurrent laryngeal nerves The nerves innervating the mucosa of the larynx is the internal laryngeal nerve from the vagus nerve. Internal laryngeal does above the vocal folds, and recurrent laryngeal does below the vocal folds

Facial anatomy

Sensory - CN V Motor (muscles of facial expression) - CN VII Main supply from ECA, main drainage to IJV

What are the three roots of ciliary ganglion?

Sensory- returning sensory info from eye (CN V1). Sympathetic- from internal carotid plexus via CN III supplies dilator pupillae m. Motor (parasympathetic) contains preganglionic axons from Cn iii to synapse in ciliary ganglion before innervating sphincter pupillae and ciliary body m.

Levels of the scalp

Skin Connective Tissue (dense) Aponeurosis Loose connective tissue Pericranium

Lateral neck muscles- superificial

Sternocleidomastoid, Trapezius

Infrahyoid muscles action innervation

Sternohyoid= ansa cervicalis (C1-C3)-depresses hyoid Omohyoid= ansa cervicalis (C1-C3)-depress hyoid Sternothyroid= ansa cervicalis (C1-C3)-depresses LARYNX thyrohyoid= C1 via CN 12 -depresses hyoid

CNVII

Stylohyoid, Posterior belly of digastric, Platysma (superficial cervical ansa)

Suprahyoid muscles- all elevate the hyoid. Innervation?

Stylohyoid= facial nerve -styloid process to body of hyoid Posterior belly of digastric= facial Anterior belly of digastric= trigeminal 5-3 (myolhyoid n. of mandibular) -mastoid process and digastric fossa to body of hyoid (tendon) mylohyoid= trigeminal 5-3 (myolhyoid n. of mandibular) -Mylohyoid line of mandible to hyoid Geniohyoid= C1 via CN 12 -mental spines of chin to hyoid

Foramen where CN VII exits skull

Stylomastoid foramen

Fasciae of the neck

Superficial fascia: platysma Deep -- Investing: surrounds all structures --Prevertebral: surrounds vertebral column & deep muscles --Pretracheal: encloses viscera --Carotid sheath: encloses neurovascular bundles (formed partially by the other 3 fasciae) -CCA, ICA, IJV, vagus n.

Superficial layer: Platysma- Innervation?

Superificial cervical ansa

4 rectus muscles and innervations

Superior Oblique- CNIV, Lateral Rectus- CNVI, everything else is CNIII

45. What ganglia provide GSA innervation to the ear?

Superior ganglion of CN X, superior ganglion of CN IX, geniculate ganglion of CN VII,

29. Identify the arteries which form Kiesselbach's plexus (the arterial plexus on the nasal septum).

Superior labial artery, anterior ethmoidal artery, greater palatine a. and septal branch of spehnopalatine artery

CNVI traverses what foramen?

Superior orbital fissure

40. Identify the cranial nerve(s) and muscle(s) used elevate the eye (i.e. look straight up).

Superior rectus (CN III) and inferior oblique (CN III)

Patient presents with miosis, anhydrosis, and ptosis... What muscle is nonfunctioning? A. Levator palpebrae superiorus B. Orbicularis oculi C. Orbicularis oris D. Superior tarsal E. Buccinator

Superior tarsal

What causes ptosis?

Superior tarsal muscle, but mostly LEVATOR PALPEBRAE SUPERIORIS

Collateral blood supply allowing subclavian to be ligated proximal to anterior scalene?

Suprascapular with dorsal scapular and circumflex scapular (subscapular) will get blood to the arm.

Spinal levels of sympathetic fibers to head

T1 - 2

With injury to the MAjOR n providing motor innervation, the tongue will deviate towards or away from the side of the lesion?

TOWARDS

Muscle that retracts mandible

Temporalis

Four muscles of mastication in the head:

Temporalis Masseter Lateral Pterygoid Medial Pterygoid Act at the temporomandibular joint (TMJ) Lateral pterygoid muscle inserts at the TMJ!

14. Identify the muscle which, when it contracts, opens the pharyngotympanic tube.

Tensor veli palatini (CN V3) and salpingopharyngeus (CN X)

Where is the interscalene nerve block administered?

The needle is inserted between palpating fingers that are positioned in the scalene groove (between anterior and middle scalene muscles). 1 = sternal head of the sternocleidomastoid muscle. 2 = clavicular head of the sternocleidomastoid muscle.

11. Where does the parotid duct open? What CN provides parasympathetic innervation to this gland? What ganglion is involved? What branch of CN V is hitch-hiked upon?

The parotid duct crosses superficial to masseter and pierces buccinators then opens into the oral cavity near the 2nd upper molar. It secretes through Stensen's Duct. Parasympathetic innervation is from CN IX the lesser petrosal n. (otic ganglion). Hitch-hikes on auriculotemporal n (CN V3).

1. What is the function of arachnoid granulations? Where are they located?

They are projections of the arachnoid membrane into the dural sinuses that allow entrance from the subarachnoid space to the venous system between outer periosteal layer and inner meningeal layer. These are only found in the median fissure.

Thyrohyoid

Thyrohyoid (C1 via CNXII): Lamina of thyroid cartilage, oblique line Body of hyoid, greater horn Depresses hyoid, raises larynx

Muscles that are innervated by CN XI

Trapezius, SCM

CN V

Trigeminal

Cranial Nerve SENSORY Ganglia

Trigeminal ggl (CNV) Geniculate ganglion (CN VII) Inferior and superior ggl. (CNIX and CNX)

CN IV

Trochlear

44. What nerve(s) innervate the mucosa of the middle ear cavity?

Tympanic nerve from CN IX

36. Where is the deep portion of the submandibular gland located?

Under the mylohyoid

what nerv testd

V1 nasociliary

Which nerve does Chorda tympani come off of?

VII

Parasympathetic supply to lacrimal gland

VII production of tears through ppg (pterygopalatine ganglion)

CN X

Vagus

5. In which layer of the scalp do the vessels travel? Muscles located? Danger layer?

Vessels travel in the dense connective tissue layer (holds vessels open), muscles travel in the aponeurotic layer (holds wound itself open) - connects , and the loose connective tissue layer is also called the danger layer as infections can be drained directly into the brain at this level.

CN VIII

Vestibulocochlear

CT scan

White bone. Light blue arrow: ramus of the mandible. Yellow arrow: masseter. Orange arrow: parotid gland. Red arrow: retromandibular vein. Blue arrow: vessel in parotid gland: external carotid artery,

Zones of neck injury: zone 1

Zone 1 extends from the clavicle to the cricoid cartilage and includes the thoracic inlet. This region contains the major vascular structures of the subclavian artery and vein, jugular vein, and common carotid artery, as well as the esophagus, thyroid, and trachea.

Zone 2: neck injury

Zone 2 extends from the cricoid to the angle of the mandible and contains the common carotid artery, internal and external carotid arteries, jugular vein, larynx, hypopharynx, and cranial nerves X, XI, and XII.

Zone 3: neck injury

Zone 3 is a small but critical area extending from the angle of the mandible to the skull base. This region contains the internal and external carotid arteries, jugular vein, lateral pharynx, and cranial nerves VII, IX, X, XI, and XII.

10. Injury to CN VII at the stylomastoid foramen leads to the individual will exhibit

a drooping of the mouth or drawing of the mouth to the affected side; collection of food between cheeks and gums or a loss of sensation deep within face. Additionally, the individual may experience the inability to whistle, wink or close their eye or wrinkle their forehead and there may be a tearing of the eye. Flaccid paralysis of all the facial expression muscles may occur on the effected side with degeneration occurring in 10-14 days. Also loss of sensastion of the affected ear.

47. List and describe the origin, course and importance of the following nerves associated with the middle ear:

a. Chorda tympani enters the tympanic cavity through the posterior cancaliculis form the facial canal and goes over the incus and exits the tympanic cavity and goes out the petrotympanic foramen and joins the lingual n. synapses in the submandibular ganglion, postganglionic axons distribute with branches of lingual n. b. Tympanic branch of IX arises from the Inferior (petrous) ganglion and ascends to the tympanic cavity through the inferior tympanic canaliculus, in the tympanic cavity it divides into branches which form the tympanic plexus, postganglionic parasympathetic fibers are distributed via the auriculotemporal nerve (form CN V) to the parotid gland **both are endangered from otitis media

6. Identify by landmarks the distribution of CN V on the face:

a. Cornea CN V1 (ophthalmic nasociliary) b. forehead CN V1 (supraorbital and supratrochlear) c. gingiva: Hard palate: Outside- V2- Posterior, middle and anterior alveolarBottom gingiva- Outside- Buccal and mental (V3) Inside- (Lingual(buccal and mental) d. lower eyelid CN V2 (infra-orbital) e. lower lip CN V3 (mental) f. nasal septum CN V2 (Nasal branches) g. roof of the mouth Greater palatine n. and nasopalatine (V2) h. tip of chin Mental (V3) i. tip of nose CN V1 (external nasal) j. tip of tongue lingual n. (CN V3) k. upper eyelid CN V1 (supraorbital) l. upper lip CN V2 (infraorbital)

Ansa cervicales (C1-C3) innervates:

all strap muscles: Omohyoid, Sternohyoid, Sternothyroid

Lesser occipital C2

along the post border of SCM

Injury just to external carotid plecus -

anhydrosis and flusing

-ascending cervical artery and phrenic nerve=

anterior surface of anterior scalene muscle

Where does ABDUCENS exit the brain?

anteriorly betw pos & medulla oblongata

Vertebral artery

arise as branches from the subclavian arteries and merge to form the single midline basilar artery. enter deep to the transverse process at the level of the 6th cervical vertebrae (C6), Once they have passed through the transverse foramen of C1 (also known as the atlas), the vertebral arteries travel across the posterior arch of C1 and through the suboccipital triangle[citation needed] before entering the foramen magnum.[1]

Greater auricular C2-3

ascends on SCM to the base of the ear. Supplies parotid region, ear, and mastoid area

The _____nerve provides sensory innervation to the temporal regions of the head, the TMJ, and general suspension from the ear

auriculotemporal nerve

Specializations of prevertebral

axillary sheath and Sibson's fascia

Bells palsy on left side-

can't use muscles on that side. Might get loud- stapedius muscle innervated by VII which helps dampen sounds as comes in ear. Hyperacusis.

Oculomtor nerve, trochlear nerve, Abducens nerve

cavernous sinus

What nerve most directly provides taste (SVA) innervation to the anterior 2/3 tongue?

chorda tympani

Right eye illuminated, consensual constriction on left side

cn 2 on right side is functional bc if not consensual, would not get reaction on right side. But didyou get direct response, no, lack of direct response, illuminate left eye. ==> C- definitlely know right CNII working, don't know wh left CNII is working.

The oculomotor nerve does not affect the dilation of the pupil, rather its stimulation results in ______

constriction (parasympathetic nerveS)

External laryngeal

cricothyroid

Torticollis

damage ot SCM or trapezius

Face vasculature: Arterial supply mainly from

external carotid artery

In Horner syndrome, to include anhydrosis, flushing, injury must be somewhere below wher _____________

external carotid comes off

What nerve is at risk with ligation of the superior thyroid artery?

external laryngeal n

What nerve runs with superior thyroid artery?

external laryngeal nerve

Innervation of Cricothyroid

external m of larynx- n external branch of superior laryngeal nerve (external laryngeal nerve). Innervation= vagus

what nerve tested

facial

Bell's palsy

facial nerve paralysis. Iatrogenic injury to VII from parotid removal

The mandibular branch of the trigeminal nerve comes through

foramen ovale and mediates motor to the muscles of mastication and sensory to the lower third of the face

External carotid branches: posterior auricular

from POSTERIOR surface of carotid, runs behind ear

Where does TROCHLEAR exit the brain?

from posterior brain stem

Where does TRIGEMINAL exit the brain?

from the pons

Which ganglia are associated with CN VII?

geniculate

The _______ ganglion contains the cell bodies for taste from the anterior 2/3 of the tongue carried by the chordae tympani branch of the facial nerve

geniculate. this branch also arries the parasympathetic supply for the submandibular and sublingual salivary glands

List the 4 EXTRINSIC tongue muscles

genioglossus, hyoglossus, styloglossus, palatoglossus

3. Costocervial trunk:

gives off 2 branches Deep cervical anastomoses with descending branch of occipital artery (ECA) Supreme intercostal for first 2 intercostal spaces

Thyrocervical trunk:

gives off 3 branches Inferior thyroid to thyroid gland. Gives off ascending cervical artery which travels with phrenic nerve on anterior scalene Transverse cervical which splits into superficial and deep transverse cervicals for trapezius and latissimus dorsi respectively. Suprascpapular runs under the clavicle, approaches the scapular notch over the transverse ligament (army over, navy under)

What nerve provides taste (SVA) innervaton to the posterior 1/3 tongue?

glossopharyngeal n

Frey's syndrome

gustatory sweating- when eat, instead of salivating=> sweating. Auriculotemporal carries sympathetics from CN v. Be concerned with auriculotemporal and sympathetics

Transverse cervical C2-3

horizontally over SCM, supplies anterolateral neck

What 2 nerves innervate skeletal muscle of the tongue?

hypoglossal, vagus

Reflexes: (In by/Out by): Corneal

in by CN V[trigeminal ganglion]. Out by CN VII

Fascial spaces and spread of infections: Retropharyngeal space

infections between the buccopharyngeal fascia and alar fascia (anterior layer of prevertebral fascia) can spread inferiorly to lower cervical levels [this space extends superiorly to the base of the skull- C7]

Fascial spaces and spread of infections: Pretracheal space

infections between the investing/infrahyoid fascia and pretracheal fascia can spread inferiorly into the superior mediastinum

Fascial spaces and spread of infections: prevertebral layer

infections deep to (i.e. contained by) the prevertebral layer can extend laterally, protruding along the posterior border of the SCM

Levator Palpebrae Superioris

innervated by Oculomotor III. If affected, Ptosis will be severe

Muscles innervated by ansa cervicalis?

innervates strap muscles Omohyoid Sternohyoid Sternothyroid

The facial nerve (VII) and vestibulocochlear (VIII) run through the _______

internal acoustic meatus. VII provides sensation of taste to anterior 2/3 tongue via chorda tympani & mediates all facial muscles, except muscles of mastication

Superior cervical ganglion provides sympathetic innervation to the face and neck regions. Sympathetics travel along the ______ and one result is pupil ________.

internal carotid artery, dilation.

Face vasculature: Venous drainage mainly into _______

internal jugular vein

Where does OCULOMOTOR exit the brain?

interpenduncular fossa

Where does CN X pass through?

jugular foramen

Where does CN XI pass through?

jugular foramen. Turns around the internal jugular vein at the tip of the anterior triangle, passes thru posterior triangle

The greater petrosal nerve, a parasympathetic branch of the facial nerve, provides innervation to the _______________

lacrimal gland in the orbit.

Where do GLOSSOPHARYNGEAL, VAGUS, ACCESSORY exit the brain?

lateral to the olive

Where do FASCIAL and VESTIBULOCOCHLEAR exit the brain?

laterally from betw pons & medulla oblongata

Horner's syndrome -

lesions of cervical sympathetic trunk (e.g. brainstem stroke, spinal cord injury) result in [F PAM]:

Which nerve is most directly responsible for general (GSA) sensation to the anterior 2/3 tongue?

lingual n

The scalp is divided into five layers: skin, dense connective tissue, aponeurosis, loose connective tissue, and periosteum. A handy mnemonic is SCALP (skin, connective tissue, aponeurosis, loose connective tissue, and periosteum). Typically, infections will be located in the ________

loose connective tissue because of the ease with which infectious agents spread via the many veins located in this region. This area is usually referred to as the "danger zone" of the scalp mainly because scalp infections here can be transmitted into the skull via emissary veins, then via diploic veins of the bone to the cranial cavity. APONEUROSIS & PERIOSTEUM

If chorda tympani is injured, p would present with ______

loss of taste (From anterior 23 of tongue), decrease in saliva production bc the submandibular and sublingual salivary glands would be denervated

Inferior alveolar nerve provides sensory innervatin to the ________

mandibular teeth

The inferior orbital fissure contains the ________________________

maxillary division of the trigeminal nerve, infraorbital vessels, and branches of the pterygopalatine ganglion.

The foramen rotundum contains the _______________

maxillary nerve. The foramen ovale contains the lesser petrosal nerve, the mandibular division of the trigeminal nerve, the accessory middle meningeal artery, and the emissary veins.

Where does HYPOGLOSSAL exit the brain?

medial to the olive

The usual symptoms for Superior Cervical Ganglion injury, commonly known as Horner's syndrome, are ______

miosis, ptosis, and anhydrosis in the head and neck region

Efferent

motor, axons leave CNS, innervate skeletal m or viscera. Visceral efferent pathways allows involve 2 neurons

CNV-3 (mandibular)

myohyoid, anterior belly of digastric

The superior orbital fissure is the opening that allows the passage of the _______

oculomotor nerve and the trochlear nerve; the lacrimal, frontal, and nasociliary branches of ophthalmic division of the trigeminal nerve; the abducens nerve; the superior and inferior divisions of the ophthalmic vein; and the sympathetic fibers from the cavernous plexus

The optic canal contains the _________________

ophthalmic artery and optic nerve, in addition to sympathetic fibers.

Ciliary ganglion

parasympathetic ganglion, contains cell bodies of neurons that innervate INTRINSIC eye mm.

The lesser petrosal nerve innervates postganglionic nerves supplying the _____

parotid gland. So look for loss of salivation

Where does glossopharyngeal nerve (CN IX) emerge from?

passes through jugular foramen

The _____________________connects the middle ear and the nasopharynx and is the conduit for spreading infections.

pharyngotympanic (eustachian) tube

Parasympathetic fibers carried by the greater petrosal branch of the facial nerve are responsible for the supply of the lacrimal gland and sinuses via _______

pterygopalatine ganglion

Injury just to internal carotid plexus -

ptosis and miosis

What nerve is at risk with ligation of the inferior thyroid artery?

recurrent laryngeal n

Recurrent laryngeal

rest of laryngeal muscles and larynx under vocal folds (sensory)

CNV maxillary traverses what foramen?

rotundum

Internal laryngeal

sensory (mucus membrane) above vocal cords

Afferent

sensory, primary afferents. Pseudounipolar cell bodies in sensory ganglia, axons enter CNS. CN vs spinal nerves

Terminal sulcus

separates anterior 2/3 from posterior 1/3

Danger space

space in the prevertebral layer: "danger space" extending to mediastinum

Middle meningeal artery traverses what foramen?

spinosum. The foramen spinosum permits the passage of the middle meningeal artery, middle meningeal vein, and the meningeal branch of the mandibular nerve

Hyperacusis

stapedius not working properly to dampen sound. Things sound louder than they should

What does CN XI accessory nerve innervate?

sternocleidomastoid, trapezius

What does facial nerve (CN VII) innervate?

stylohyoid and posterior belly of digastric

Mm. inntervated by CVII

stylohyoid, posterior belly of digastric, platysma (superficial cervical ansa)

Where does facial nerve (CN VII)) emerge from?

stylomastoid foramen

Facial nerve exits base of skull via ________

stylomastoid foramen. Sends posterior nerve to posterior auricular n to posterior auricular m. and occipital belly of occipitofrontalis. Passes deep to parotid gland,

The arachnoid villi allow CSF to pass between which 2 of the following spaces?

subarachnoid space and superior sagittal sinus. The arachnoid villi are extensions of the arachnoid mater into the superior sagittal sinus

Which ganglia are associated with auricular branch of CN X?

superior ganglion of face

TMJ is a

synovial joint, two joint cavities separated by fibrocartilaginous disc

What dampens sound?

tensor tympani, stapedius

External carotid branches: Superficial temporal

terminal branch, runs in front of ear

External carotid branches: Maxillary

terminal branch, to infratemporal fossa and pterygopalatine fossa

The glossopharyngeal nerve provides taste innervation to _____

the posterior third of the tongue and sensation related to the gag reflex

Course and function of CN XI (accessory)

through jugular foramen, around IJV towards posterior triangle behind SCM. Innervates SCM and trapezius

Course and function of CN VII(Facial)

through stylomastoid foramen. Innervates stylohyoid, posterior belly of digastric, joins tranverse cervical (c2,c3) to innervate platysma (superficial cervical ansa)

Vertebral:

through transverse foramen into skull (foramen magnum) and forms basilar artery

Course and function of CN XII, Hypoglossal

thru hypoglossal canal, goes betw ICA & IJV, curves around occipital a. Passes on surface of hyoglossus behind mylohyoid. Motor innervation to tongue. Receives fibers from C1 and forms ansa cervicalis

Course and function of CN X, Vagus

thru jug foramen, forms inf sensory ggl, behind ICA & IJV in carotid sheath. Branches into pharyngeal, carotid body, cardiac branches, superior laryngeal n, recurrent laryngeal n

Course and function of CN IX (glossopharyngeal

thru jugular foramen, runs between ICA and IJV and curves around stylopharyngeus and goes deep to hyoglossus. Innervates stylopharyngeus, carotid body & sinus, gives sensory to PHARYNX

Sternocleidomastoid

tilt head on same side, rotate face towards the opposite side, together draw head forward

Top picture: Bottom picture

top: lesion on right CNII- can't sense light- nothing happens. With left, everything normal => CNIII good on both Bottom- left- consensual response but not direct response. On other side, direct, but not, consensual. To get consensual, must have II, must be able to sense light => CNII fine

Drooping of right shoulder occurs as a result of paralysis of _________

trapezius as a result of injury to right ACCESSORY NERVE. Loss of the accessory n would also result in weakness in turning the head to left, a function of the right SCM

Which ganglia are associated with auriculotemporal (CN V)?

trigeminal ganglion

What nerve tested?

v1

What nerv tested

v3

Which ganglia are aassociated with lesser occipital (C2,3) and greater auricular (C2, 3)?

ventral rami, DRG