Cranial Nerve Examination

Question 1

1 - Olfactory Nerve

Answer 1

This is only usually tested if the patient reports an alteration in their sense of smell.
If required, you should either use olfactory testing bottles or easily-recognised scents such as soap and coffee. Test each nostril separately, occluding the contralateral nostril by compressing it with your finger. Do not use noxious substances as these can stimulate the pain fibres in the trigeminal nerve.

Question 2

Optic Nerve (2)

Answer 2

-Test visual acuity in each eye separately. If a Snellen chart is unavailable, can hold up fingers. Ask if they normally wear glasses.
-Test visual fields
-Test for inattention/visual extinction
-Test direct and consensual light reflexes
-Swinging light
-Test accommodation

Question 3

Oculomotor (3), Trochlear (4), Abducens Nerves (6)

Answer 3

Ask the patient to keep their head still and to follow your finger with their eyes. Slowly trace a large H shape and a central I shape with your finger, taking the patients eyes to the limit of their gaze as you do so. Ask the patient if they experience any diplopia. Observe for dysconjugate eye movements and for nystagmus.

Question 4

Trigeminal Nerve (5)

Answer 4

• Test sensation in the skin supplied by the ophthalmic, maxillary and mandibular nerves. Ask if there’s a difference in the strength of sensation between both sides.
  -Test the motor component by asking the patient to clench their teeth and palpate the contraction of the masseter and temporalis muscle. Ask them to open their mouth against resistance. Look for jaw deviation.
  -Jaw jerk
  (Corneal reflexes are not routinely performed)

Question 5

Facial Nerve (7)

Answer 5

Ask the patient to:
-sure up their eyes and not let them to be open but you
-puff out their cheeks
-raise their eyebrows
-purse their lips
-show you their teeth

Question 6

Vestibulocochlear nerve (8)

Answer 6

• Cover the opposite ear with your hand and whisper a number to the patient. Ask them to repeat it.
• If an abnormality is suspected, perform Rinnes and Weber’s tests to determine whether this is a sensory or conductive deficit

Question 7

Glossopharyngeal (9) and Vagus (10) nerves

Answer 7

• Ask the patient to open their mouth wide and assess whether the uvula is in the midline at rest.
• Ask the patient to say ‘aah’ and note any asymmetry of movement. The uvula will deviate away from the side of a glossopharyngeal nerve palsy.
• Ask whether the patient has any difficulty swallowing. The gag reflex is unpleasant and does
  not need to be performed routinely
• Ask the patient to cough

Question 8

Accessory nerve (11)

Answer 8

Test the trapezius by asking the patient to shrug their shoulders against resistance.
Test the power in the sternomastoids by asking the patient to turn their head against resistance. Palpate the body of the sternomastoid muscle with your free hand whilst doing so.

Question 9

Hypoglossal (12)

Answer 9

Ask the patient to open their mouth and observe their tongue at rest for fasciculation.
Ask them to protude their tongue and note any deviation - Deviation will occur toward the side of a hypoglossal nerve lesion.
Ask the patient to push their tongue into their cheek agaisnt the resistance of your finger and assess the power in their tongue.