Cranial nerves

Question 1

CN I

Answer 1

Olfactory nerve- forebrain
Nerve exits: cribriform plate in ethmoid bone
Special sense- smell

Question 2

CN II

Answer 2

Optic -forebrain
Exits: optic canal in sphenoid
special sense- vision

Question 3

CN III

Answer 3

oculomotor -midbrain
exits: superior orbital fissure
somatic motor fibers- muscles of eye (-2)
» superior division: sup rectus and levator palebrae. everything else is inferior division
PSNS- synapses at cilliary ganglion

Question 4

CN IV

Answer 4

Trochlear nerve -midbrain
exits: superior orbital fissure
Somatic motor fibers: superior oblique eye muscle (exception to CN III eye muscles)

Question 5

CN V

Answer 5

Trigeminal- sensory and motor root

contains 3 separate portions

Question 6

CN VI

Answer 6

Abducent
Exits: superior orbital fissue
Somatic motor fibers: Lateral rectus eye muscle (exception to the CN III eye mucles rule)
- most likely to have problems becuase it is ver close to the carotid artery in the cavernous sinus

Question 7

CN VII

Answer 7

Facial Nerve
Exits: internal acoustic meatus Exits skull: stylomastoid foramen
somatic motor fibers- ANY muscle of facial expression and stylohyoid and post digastric
> motor branches (temporal, zygomatic, buccal, marginal/mandibular, and carvical)
Somatic sensory- region of ext ear
-takes some taste signals
PSNS- 1. pterygopalantine 2. submandibular

Question 8

CN VIII

Answer 8

Vestibulocochlear
Exits: internal external meatus
special sense: hearing and balance

Question 9

CN IX

Answer 9

Glossopharyngeal
Exits- jugular foramen
smoatic motor fibers- stylopharyngeus muscle
somatic sensory- post 1/3 of toungue, pharynx and mid ear
visceral sensory- carotid body and sinus
-takes some taste senory( post 1/3)
PSNS- otic ganglion: presynaptic to tympanic plexus and lesser petrosal (gland tissue activation)

Question 10

CN X

Answer 10

Vagus
Exits- jugular foramen
Somatic motor fibers: muscles of larynx, pahrynx (-1 stylopharyngeus IX), and palate (-1)
Somatic sensory: pharynx, larynx, and external ear canal
Visceral sensory: pharynx, throasic forgut and midgut viscera
-takes some taste snses (POST 1/3)
PSNS- no head ganglions

Question 11

CN XI

Answer 11

Spinal accessory
Exits- jugular foreamen
Somatic motor fibers- sternocleidomastoid and trapezius

Question 12

CN XII

Answer 12

Hypoglossal
Exits- hypoglossal canal
Somatic motor fibers: muscles of the toungue (-1) (palatoglossus)
runs over the hyoglossal muscle

Question 13

Hitchkiking on hypoglossal nerve

Answer 13

Anterior rami of C1

• superior root of ansa cervicalis
• geniohyoid
• nerve to thyrohyoid

Question 14

V1

Answer 14

Opthalmic nerve
Exits: superior orbital fissure
Somatic sensory: orbit, central forehead, and dorsum of the nose
>sensory Branches:
In orbit Frontal> supraorbital+supratrochlear: scalp ^eyelid
Lacrimal : skin of lacrimal region and ^ eyelid
Out of suprior orbital fissure: Nasocilliary nerve> short cilliary +long cilliary+ethmoid+infratrochlear: eye,sup nasal cv, bridge of nose, dorsum of nose
external nasal

Question 15

V2

Answer 15

Maxillary
Exits: foramen rotundum
Somatic sensory: lateral forehead, lateral nose, nasal cavity, palate, and upper lip
> sensory branches (zygomaticotemporal, zygomaticofascial, and infraorbital)
-superior alveolar nerves (maxillary teeth)

Question 16

V3

Answer 16

Mandibular nerve
Exits: foramen ovale
somatic motor fibers-muscles of masstication and “tensor muscles” + mylohyoid and anterior branch of digastric
> sensory branches ( auriculotemporal, buccal, mental)
-Post synaptic PSNS from CN IX hitchhike on auriculotemporal nerve to parotid gland
- inferior alveolar branch of CN V3 > mandibular teeth
-lingual: gen sensation for ant toungue
- Chorda tympani HH frpm VII for taste

Question 17

Major branches of the V1 opthalmic nerve

Answer 17

Supraorbital, supratrochlear, Lacrimal, infratrochlear, external nasal