Introduction

Aim: to perform a screening test of the main functions of the cranial nerves.

Position: Sitting over the edge of the bed/on a chair is ideal.

Inspection

In the face, look for:

• Ptosis
• Pupillary inequality
• Facial asymmetry
• Skin (erythema, sweating, scars, etc.)

I

Olfactory

• Ask about recent changes in sense of smell/taste.

II

Optic

• Acuity (one eye at a time with Snellen chart & accommodation [also III])
• Fields
• Reflexes
• Opthalmoscopy (fundoscopy)

III/IV/VI

Oculomotor/Trochlear/Abducens

• Eye movements (move your finger slowly and smoothly in a 'H' shape and ask the patient to follow)
• Ask about double vision (diplopia), look for nystagmus

V

Trigeminal

• Facial sensation in the three branches (ophthalmic, maxillary, mandibular)
• Muscles of mastication

VII

Facial

• Look for facial weakness/asymmetry/loss of forehead creases
• Upper motor neurone lesions = forehead crease sparing (bilateral innervation) - Raise eyebrows
• Screw up eyes
• Puff cheeks out
• Grin (show teeth)

VIII

Vestibulocochlear

• Whisper in one ear while occluding/distracting the other
• Rinne/Weber test with tuning fork

IX/X

Glossopharyngeal/Vagus

• Say 'ahh' and look for uvula deviation (away from side of lesion)
• Swallowing problems
• Gag reflex (not in routine examination)

XI

Accessory

• Shrug shoulders against resistance (trapezius)
• Turn head to side against resistance (sternocleidomastoid) - weakness in turning head right is due to left sided muscle weakness

XII

Hypoglossal

• Fasciculations/wasting of tongue as it rests in mouth - lower motor neurone signs
• Stick tongue out/move side to side ? look for deviation (towards side of lesion)