Clinical Examination - Cranial Nerves

Question 1

Name the cranial nerves 1-12

Answer 1

1) Olfactory
2) Optic
3) Occulomotor
4) Trochlear
5) Trigeminal
6) Abducens
7) Facial
8) Vestibulocochlear
9) glossopharyngeal
10) Vagus
11) Accessory
12) Hypoglossal

Question 2

How would you test the function of the optic nerve?

Answer 2

• Inspection of the pupil
  
  • The size
  • Shape
  • Symmetry
• Assess Visual Acuity
  
  • Have the patient stand 6 metres away from a snellen chart
  • Get them to read out the letters.
  • Record the result as the chart distance (numerator) over the number of the lowest line read (denominator). If the patient reads the 6/6 line but gets 2 letters incorrect, you would record as 6/6 (-2).
• Visual Neglect
  
  • Wiggling hands on either side and testing if they can point to which hand is wiggling.
  • Remember to both at the same time.
• Visual Fields
  
  • Positions yourself close to patient. Both of you cover the eye on the same side. Have your hand equidistant between you and the patient. Move your hand outside of your periphery. then move it just within your periphery. Ask the patient to say when they can see you wiggling your hand
  • You can ask the patient if any part of your face is missing to test for central visual field problems, also offer to use an amsler chart.
• Blind spot
  
  • Cover one eye
• Reflexs
  
  • Both eyes Pupillary reflex
  • Swinging Torch Test
  • Accomodation Reflex
• Offer:
  
  • Snellen Chart if not already done so
  • Ischihara plates
  • Fundoscopy

Question 3

How would you test the function of the oculomotor, trochlear and abducens nerve

Answer 3

• Inspect the eyelids for evidence of ptosis
• Ask the patient to focus on something and ask if they have any double vision
• Do the H test.
• Hirshburg test/corneal reflex test/light reflex test.
  
  • You shine a light in the patients eyes and get them to focus on it. See if the reflection of light is central in both eyes
• Cover test
  
  • get the patient to fixate on something then have them cover one eye and look for any deviation.

Question 4

What are the three divisions of the trigeminal nerve and how would you test them?

Answer 4

(V1) Ophthalmic

(V2) Maxillary

(V3) Mandibular

Ask the patient to close their eyes and say ‘yes’ each time they feel you touch their face.

Assess the sensory component by testing light touch and pinprick sensation across the:

• Forehead (lateral aspect): ophthalmic (V1)
• Cheek: maxillary (V2)
• Lower jaw (avoid the angle of the mandible as it is supplied by C2/C3): mandibular branch (V3)

Inspect and palpate the temporalis and masseter muscles whilst the patient clenches their jaw.

Test for the Jaw Jerk reflex

• Ask the patient to open their mouth.
• Place your finger horizontally across the patient’s chin.
• Tap your finger gently with the tendon hammer.

Test for Corneal Reflex (jab them in the eye and see if they blink)

Question 5

How would you test the function of the facial nerve?

Answer 5

Ask if they have any change to their sense of taste

Ask about any change in their hearing

Inspect for facial asymmetry

Get them to pull the birthday cake faces.

Question 6

How would you test the functions of the vestibulocochlear nerve?

Answer 6

• Gross hearing test
• Rhines and Webers (will test in a later flash card)
• Unterberger Test
  
  • Have the patient march on the spot with their arms outstretched and their eyes closed. If there is a lesion on the VIII nerve they will turn towards the lesion.
• Test for the vestibulocochlear reflex
  
  • Have the patient fixate on you then rapidly turn their head to the side. Their eyes should remain fixed on you. The side on which there is a lesion will lose fixation.
• Offer otoscopy

Question 7

How would you test the functin of the glossopharyngeal and vagus nerve?

Answer 7

• Ask the patient if they have experienced any issues with swallowing, as well as any changes to their voice or cough.
• Visulise the uvula, ask the patient to say ‘ahh’
  
  • A vagus nerve palsy will make the uvula deviate away from the lesion
• Ask them to cough
• Offer gag reflex
• Swallow assessment with water
• Ask the patient to say British Constitution

Question 8

How would you test the function of the accessory nerve?

Answer 8

• Ask the patient to shrug against resistance
• Ask the patient to turn their head against resistance.

Question 9

How would you test the function of the hypoglossal nerve?

Answer 9

• Inspect tongue at rest
  
  • Wasting and fasciculations in motor neuron disease
  • Tongue deviation towards side of lesion in LMN pathology
• Test power of tongue against each cheek

Question 10

What might cause a patient to have a reduced sense of taste and smell?

Answer 10

• Mucus blockage of the nose
• head trauma
• Parkinsons
• Covid19
• Congenital

Question 11

Recall some causes of decreased visual acuity

Answer 11

Refractive errors

Optic nerve pathology such as optic neuritis

Lesions higher in the visual pathway

Amblyopia (Lazy eye)

Cataracts and Corneal Scarring

Age related macular degeneration