Cranial Nerves

Question 1

Which cranial nerves are strictly sensory?

Answer 1

Olfactory (I)
Optic (II)
Vestibulocochlear (VIII)

Question 2

Which cranial nerves are strictly motor?

Answer 2

Oculomotor (III)
Trochlear (IV)
Abducens (VI)
Accessory (XI)
Hypoglossal (XII)

Question 3

Which cranial nerves are both motor and sensory?

Answer 3

Trigeminal (V)
Facial (VII)
Glossopharyngeal (IX)
Vagus (X)

Question 4

What is the function of the olfactory nerve? How is it tested?

Answer 4

Sense of smell

Test: Identify familiar odors

Question 5

What is the function of the optic nerve? How is it tested?

Answer 5

Responsible for vision

Test: Visual field test

Question 6

What is the function of the oculomotor nerve? How is it tested?

Answer 6

Upward, downward and medial gaze

Test: Reaction to light and visual tracking

Question 7

What is the function of the trochlear nerve? How is tested?

Answer 7

Downward and inward gaze

Test: Depression of eye (looking downward)

Question 8

What is the function of the trigeminal nerve?

Answer 8

Touch and pain: skin of face, mucous membranes of the nose, sinuses, mouth, anterior tongue

Voluntary motor: Muscles of mastication

Question 9

How is the trigeminal nerve tested? (3)

Answer 9

Corneal reflex
Face sensation
Clench teeth; push down on chin to separate jaw

Question 10

What is the function of the abducens nerve? How is tested?

Answer 10

Lateral gaze

Test: Abduct the eye without rotating the head

Question 11

What is the function of the facial nerve?

Answer 11

Taste: Anterior tongue
Voluntary motor: facial muscles
Autonomic motor: lacrimal, submandibular, and sublingual glands

Question 12

How is the facial nerve tested?

Answer 12

Close eyes tight
Smile and show teeth
Whistle and puff out cheeks
Identify familiar tastes (i.e. sweet/sour etc.)

Question 13

What is the function of the vestibulocochlear nerve? How is tested?

Answer 13

Hearing and balance

Test: Hear watch ticking, hearing tests, balance and coordination tests, Weber and Rinne test (tuning fork)

Question 14

What is considered a positive test for possible vestibulocochlear damage when hearing a watch ticking?

Answer 14

Inability to hear the ticking sound at 18-24 inches from the ear

Question 15

What is the function of the glossopharyngeal nerve? How is tested?

Answer 15

Touch/Pain: Posterior tongue and pharynx
Taste: Posterior tongue
Voluntary motor: Select muscles of pharynx
Autonomic: Parotid gland

Test: Gag reflex and ability to swallow

Question 16

What is the function of the vagus nerve? How is it tested?

Answer 16

Touch/Pain: Pharynx, larynx and bronchi
Taste: Tongue and epiglottis
Voluntary motor: muscles of palate, pharynx and larynx
Autonomic: Thoracic and abdominal viscera

Test: Say “Ahhh,” gag reflex, ability to swallow

Question 17

What is the function of the accessory nerve? How is it tested?

Answer 17

Voluntary motor: SCM and trapezius muscles

Test: Resisted shoulder shrug

Question 18

What is the function of the hypoglossal nerve? How is it tested?

Answer 18

Voluntary motor: muscles of the tongue

Test: Tongue protrusion (positive sign = tongue deviates toward injured side)