Cranial Nerves

Question 1

CN I: Olfactory Nerve

Answer 1

Function: Sense of smell, olfaction
Exit Point: Cribiform Plate
Course:
Common Clinical Disorders: Anosmia (loss of smell, one-sided are normally unaware because of functioning other side, bilateral often accompanied with decreased taste; causes: head trauma, viral infectinos, PD, Az, intracranial lesions)

Question 2

CN II: Optic Nerve

Answer 2

Function: Vision
Exit Point: Optic Canal
Course:
Common Clinical Disorders:

Question 3

Function: Eye movements (levator palpebrae superior and all extraocular muscles except for superior oblique and lateral rectus), Pupil constriction (pupil constrictor and ciliary muscles)
Exit Point: Superior Orbital Fissure
Course:
Common Clinical Disorders:

Answer 3

CN III: Oculomotor Nerve

Question 4

CN IV: Trochlear Nerve

Answer 4

Function: Facial sensation, muscles of mastication, tensor tympani
Exit Point: V1 (opthalic): Superior Orbital Fissure; V2 (maxillary): Foramen Rotundum; V3 (mandibular): Foramen Ovale; Mnemonic - Single Room Occupancy
Course:
Common Clinical Disorders: Trigeminal Neuralgia (brief severe pain, provoked by chewing/shaving/etc, unknown cause. can occur in MS pts, initial treatment with medications)

Question 5

Function: Eye movement (lateral rectus - abduction)
Exit Point:Superior Orbital Fissure (through Dorello’s canal)
Course:
Common Clinical Disorders:

Answer 5

CN VI: Abducens Nerve

Question 6

Function: Muscles of facial expression (also stapedius and part of digastric), taste (anterior 2/3), lacrimation, salivation
Exit Point: Auditory canal (stylomastoid foramen)
Course:
Common Clinical Disorders: Bell’s Palsy (divisions impaired, gradual recovery, unilateral LMN facial weakness, probably viral or inflammatory cause, normal MRI, medicated with oral steroids, 80% full recovery in 3 weeks)

Answer 6

CN VII: Facial Nerve

Question 7

CN VIII: Vestibulocochlear Nerve

Answer 7

Function: hearing, balance and equilibrium
Exit Point: Auditory Canal
Course:
Common Clinical Disorders: Hearing loss, Vertigo

Question 8

CN IX: Glossopharyngeal Nerve

Answer 8

Function: pharyngeal muscles, carotid body reflexes (chemo and baroreceptors), salivation, taste (posterior 1/3)
Exit Point: Jugular Foramen
Course:
Common Clinical Disorders:

Question 9

CN X: Vagus Nerve

Answer 9

Function: Parasympathetics to most organs, laryngeal muscles (voice), pharyngeal muscles (swallowing), aortic arch reflexes, taste from epiglottis
Exit Point: Jugular Foramen
Course:
Common Clinical Disorders:

Question 10

CN XI: Spinal Accessory Nerve

Answer 10

Function: Head turning (upper trapezius and sternomastoid muscles)
Exit Point: Jugular Foramen (enters skull via foramen magnum)
Course:
Common Clinical Disorders:

Question 11

Function: Tongue movement (intrinsics)
Exit Point: Hypoglassal Canal
Course:
Common Clinical Disorders:

Answer 11

CN XII: Hypoglossal Nerve

Question 12

UMN weakness vs LMN weakness

Answer 12

LMN all the way up forehead contralateral side

UMN eye-level downward weakness

Question 13

Sympathetic v. parasympathetic nervous system

Answer 13

sympathetic nervous system=fight or flight response

parasympathetic nervous system=rest and digest or perform the automatic functions of the body.

Question 14

meumonic for remembering cranial nerves in order

Answer 14

On Old Olympus Tower Top A Fin and German Viewed Some Hops