Cranial Nerves

Question 1

Cranial Nerve I

Answer 1

Olfactory: Sense of smell
Test: present with a non-irritating odor

Question 2

Cranial Nerve II

Answer 2

Optic: vision
Test: Visual acuity, visual fields by confrontation, pupillary light reaction, near response

Question 3

Cranial Nerve III

Answer 3

Oculomotor: Pupillary constriction, opening the eye (lid elevation), and most EOMs
Test: Pupillary light reaction, near response (constriction and accommodation), EOMs, convergence

Question 4

Cranial Nerve IV

Answer 4

Trochlear nerve: Downward, internal rotation of the eye

Test: EOMs, convergence

Question 5

Cranial Nerve V

Answer 5

Trigeminal nerve

1. ophthalmic: sensory information from the upper part of the face, including forehead, scalp and upper eyelids
2. maxillary: sensory information from the mid-face, including cheeks, upper lip and nasal cavity
3. mandibular: sensory information from ears, lower lip, chin; controls movement of muscles within jaw and ear

Test: Motor-clench teeth, open jaw, move side to side; Sensory-pain on forehead, cheeks, and chin; corneal reflex-touch cornea with cotton

Question 6

Cranial Nerve VI

Answer 6

Abducens nerve: associated with lateral rectus muscle - outward eye movement
Test: Six cardinal fields of gaze, convergence

Question 7

Cranial Nerve VII

Answer 7

Facial nerve: moving muscles used for facial expressions, provides taste for most of the tongue, salivary glands and tear-producing glands, outer ear sensation

Test: facial movements (expression, closing the eye, closing the mouth); taste for salty, sweet, sour and bitter; sensation from the ear

Question 8

Cranial Nerve VIII

Answer 8

Vestibulocochlear nerve: balance & hearing

Test: Whispered voice test, Rinne and Weber

Question 9

Cranial Nerve IX

Answer 9

Glossopharyngeal nerve: sensory info from sinuses, back of the throat, parts of inner ear, back part of the tongue; sense of taste to the back of the tongue; stimulates voluntary movement of a muscle in the back of the throat

Test: Difficulty swallowing, movement of soft palate and the pharynx (symmetric), uvula midline

Question 10

Cranial Nerve X

Answer 10

Vagus nerve: communicates sensory info from ear canal and parts of throat, organs in chest and trunk; motor control of throat muscles; stimulates muscles of organs in chest/trunk; provides sense of taste near the root of the tongue

Test: Difficulty swallowing, movement of soft palate and the pharynx (symmetric), uvula midline

Question 11

Cranial Nerve XI

Answer 11

Accessory nerve: motor nerve controls the muscles in the neck

Test: Look for atrophy or fasciculations, shrug against resistance, turn head to each side against hand, observe the contraction of the opposite SCM muscle and note the force of the movement against your hand

Question 12

Cranial Nerve XII

Answer 12

Hypoglossal nerve: tongue motor movement

Test: Tongue protrude midline, move tongue side to side and note symmetry

Question 13

Cranial nerve tests in infants:
II
II & III
III, IV & VI

Answer 13

II: visual acuity
II, III: response to light
III, IV, VI: extraocular movements

Question 14

Cranial nerve tests in infants:
V
VII
VIII

Answer 14

V: motor - rooting reflex, sucking reflex
VII: Facial - observe infant crying/smiling, note facial symmetry
□ Congenital facial nerve palsy can result from birth trauma or developmental defects
VIII: acoustic - acoustic blink reflex, tracking in response to sound

Question 15

Cranial nerve tests in infants:
IX & X
XI
XII

Answer 15

IX, X: swallow & gag
□ Dysphagia: injury to IX, X, XII
XI: spinal accessory - symmetry of shoulders
XII: hypoglossal - coordination of sucking, swallowing, tongue thrusting; pinch nostrils - observe for reflex opening of the mouth