Cranial nerves

Question 1

Cranial nerve 1

Answer 1

Olfactory nerve

Function: Smell (sensory)

Test: Ask the patient to identify familiar odours (e.g., coffee, vanilla) with eyes closed, one nostril at a time

Question 2

Cranial nerve 2

Answer 2

Optic nerve

Function: Vision (sensory)

Test:
- Visual acuity (Snellen chart)
- Visual fields (confrontation test)
- Fundoscopy (inspect optic disc)
- Pupillary light reflex (afferent limb)

Question 3

Cranial nerve 3

Answer 3

Oculomotor nerve

Function: Eye movement, eyelid elevation, pupil constriction

Test:
- Check eye movements
- Pupillary light reflex
- Accommodation reflex

Question 4

Cranial nerve 4

Answer 4

Trochlear nerve

Function: Eye movement – superior oblique (moves eye down and in)

Test: Ask patient to follow finger as you move it downward and inward

Question 5

Cranial nerve 5

Answer 5

Trigeminal nerve

Function:
- Sensory to face (V1 - ophthalmic, V2 – maxillary, V3 – mandibular)
- Motor to muscles of mastication

Test:
- Light touch/pinprick to 3 facial zones
- Corneal reflex (sensory limb – V1)
- Palpate masseter and temporalis while patient clenches jaw

Question 6

Cranial nerve 6

Answer 6

Abducens nerve

Function: Eye movement – lateral rectus (abducts eye)

Test: Ask patient to follow finger to the side (lateral gaze)

Question 7

Cranial nerve 7

Answer 7

Facial nerve

Function:
- Motor to muscles of facial expression
- Taste to anterior 2/3 of tongue

Test:
- Ask patient to smile, frown, raise eyebrows, puff cheeks
- Test taste

Question 8

Cranial nerve 8

Answer 8

Vestibulochoclear nerve

Function: Hearing and balance (sensory)

Test:
- Hearing: Whisper test, Rinne (air vs. bone), Weber (lateralization)
- Balance: Romberg test, observation of gait

Question 9

Cranial nerve 9

Answer 9

Glossopharangeal nerve

Function:
- Taste and sensation from posterior 1/3 of tongue
- Swallowing
- Gag reflex (sensory limb)
- Parasympathetic to parotid gland

Test:
- Gag reflex
- Observe swallowing

Question 10

Cranial nerve 10

Answer 10

Vagus nerve

Function:
- Motor to pharynx, larynx (speech, swallowing)
- Parasympathetic to thoracoabdominal viscera
- Gag reflex (motor limb)

Test:
- Observe palate elevation (“ah” test – uvula should rise midline)
- Gag reflex
- Listen to speech for hoarseness

Question 11

Cranial nerve 11

Answer 11

Accessory nerve

Function: Motor to sternocleidomastoid and trapezius

Test:
- Shoulder shrug against resistance (trapezius)
- Turn head against resistance (sternocleidomastoid)

Question 12

Cranial nerve 12

Answer 12

Hypoglossal nerve

Function: Tongue movement (motor)

Test:
- Ask patient to protrude tongue (deviation = lesion toward affected side)
- Check for fasciculations or atrophy