Cranial Nerves

Question 1

CN I

Answer 1

Ophthalmic
Cribriform plate
Special sensory
Smell (olfaction)
Effect of lesion: anosmia- loss of smell

Question 2

CN II

Answer 2

Optic
Optic canal
Special sensory
Vision
Effect of lesion- blidness

Question 3

III

Answer 3

Oculomotor
Superior orbital fissure
Somatic motor- eye movement
-Lesion: loss of eye movement
Visceral motor- constricts pupil, focus lens
-Lesion: pupil is dilated, can’t focus near objects

Question 4

IV

Answer 4

Trochlear
Superior orbital fissure
Somatic motor
Eye movement
Lesion: impairs SO m. (causes paresis of vertical gaze)

Question 5

V

Answer 5

Trigeminal
V1- Ophthalmic Branch- Superior orbital fissure, all sensory superior to upper eyelid
-Somatic sensory
-Touch, pain, temp of face, tongue
-Lesion: numbe face, tongue
V2- Maxillary Branch- Foramen Rotundum, All sensory between lower eyelid and upper lip
V3- Mandibular Branch- Foramen Ovale, Sensory and motor
V2+V3
-Somatic (brachial) motor- 1st pharyngeal arch
-Muscles of mastication, tensor tympani m., tensor veli palatini m., anterior belly of diagastric m., mylohyoid m.
-Lesion: trouble chewing and dampering loud sounds

Question 6

VI

Answer 6

Abducens
Superior orbital fissure
Somatic motor
Eye movement
Lesion: eye does not move laterally

Question 7

VII

Answer 7

Facial
Internal acoustic meatus
stylomastoid foramen

Somatic (brachial) motor- 2nd pharyngeal arch
-Muscles of facial expression, stapedius, stylohyoid, post. belly of diagastric m.
-Lesion: can’t smile, frown, wink (Bell’s Palsy)

Visceral (parasympathetic) motor
-Lacrimal, nasal, submandibular gland, sublingual gland
-Lesion: dry eye, nose, mouth

Special sensory (taste)
-Taste to anterior 2/3 tongue
-Lesion: can’t taste on the anterior tongue

Somatic (general) sensory
-Sensory near external acoustic meatus
-Lesion: sensory loss to the area

Question 8

VIII

Answer 8

Vestibulocochlear
Internal acoustic meatus
Special sensory
Vestibular (balance), auditory (hearing), motion (acceleration/deceleration)
Lesion: loss of balance, dizziness, deafness

Question 9

IX

Answer 9

Glossopharyngeal
Jugular foramen

Special sensory
-Taste posterior 1/3 of tongue and pharynx
-Lesion: can’t taste on posterior tongue

Visceral sensory
-Chemoreceptors (carotid body) and baroreceptors (carotid sinus)

Somatic (general) sensory
-Posterior auricle, tragus, posterior 1/3 of tongue, soft palate and pharynx, afferent limb of gag reflex
-Tympanic cavity and membrane, pharyngotympanic tube, mastoid cells

Somatic (brachial) motor – 3rd pharyngeal arch
-Stylopharyngeus mm. (minor swallowing

Visceral (parasympathetic) motor -Parotid gland (secretes saliva)
-Lesion: dry mouth

Question 10

X

Answer 10

Vagus
Jugular foramen

Somatic (general) sensory
-Sensations from Auricle, external acoustic meatus, and dura mater or posterior cranial fossa

Special sensory (taste)
-Epiglottis and palate

Visceral sensory
-Base of tongue, pharynx, larynx, trachea, bronchi, heart, esophagus, stomach, intestine to L colic flexure, afferent limb of cough reflex

Somatic (brachial) motor
-Soft palate m, pharyngeal constrictor m, Intrinsic laryngeal mm, palatoglossus, upper 2/3 of esophagus, motor limb gag reflex

Visceral (parasympathetic) motor
-Smooth m. of trachea, bronchi, digestive tract and cardiac m.

Question 11

XI

Answer 11

Accessory
Jugular foramen
Somatic Motor Sternocleidomastoid and Trapezius mm

Question 12

XII

Answer 12

Hypoglossal
Hypoglossal canal
Somatic Motor
Intrinsic and extrinsic mm of the tongue (except palatoglossal m.) Lesion: Slurred speech, withered tongue, tongue points to side of lesion, difficulty swallowing