Cranial Nerve Examination 

A cranial nerve examination is a core part of neurological assessment in the Emergency Department. MRCEM examiners expect a systematic yet focused approach that can be adapted to a patient’s presenting complaint. This guide outlines an efficient, ED-relevant method for examining the cranial nerves.

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Principles for the MRCEM OSCE

• Perform a targeted examination based on symptoms (e.g., headache, diplopia, facial droop, dizziness).

• Verbalise your actions clearly.

• Focus on CN II–VIII, the ones most relevant in acute presentations.

• Avoid unnecessary tests (e.g., smell testing unless specifically indicated).

• Be able to summarise findings and link them to likely pathology.

Cranial Nerve Examination (I–XII)

Cranial Nerve I (Olfactory)

Rarely examined in ED unless specifically indicated. Ask about recent changes in smell.

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Cranial Nerve II (Optic)

Visual Acuity

Use Snellen chart or near card. Test each eye with glasses if normally worn.

Visual Fields

Use confrontation testing in all quadrants.

Pupillary Reflexes

Assess:

• Direct response

• Consensual response

• Perform swinging light test if needed (checks for RAPD)

Colour Vision (Optional)

Useful in suspected optic neuritis.

Visual Inattention

Important in stroke assessment.

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Cranial Nerves III, IV, VI (Oculomotor, Trochlear, Abducens)

Test extraocular movements using the H-pattern.

Observe for:

• Diplopia

• Nystagmus

• Ptosis

• Restricted movement

CN III palsy with pupil involvement is an emergency (possible aneurysm).

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Cranial Nerve V (Trigeminal)

Sensory

Assess light touch in all three divisions:

• V1 – forehead

• V2 – cheek

• V3 – jaw

Motor

• Clench teeth (masseter & temporalis)

• Jaw opening & deviation

Corneal Reflex

Not routinely required in OSCE unless verbally stated.

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Cranial Nerve VII (Facial)

Test:

• Raise eyebrows

• Close eyes tightly

• Smile

• Puff cheeks

UMN lesion: forehead sparing (stroke)
LMN lesion: whole side affected (Bell’s palsy)

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Cranial Nerve VIII (Vestibulocochlear)

Hearing

Whisper test or finger rub.

Vestibular Function

Ask about vertigo; observe for nystagmus.

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Cranial Nerves IX & X (Glossopharyngeal & Vagus)

Assess:

• Speech quality

• Palatal elevation (“Say ahh”)

• Uvula position

Gag reflex not routinely required.

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Cranial Nerve XI (Accessory)

• Shoulder shrug (trapezius)

• Head turn against resistance (sternocleidomastoid)

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Cranial Nerve XII (Hypoglossal)

• Tongue protrusion (deviation toward lesion)

• Inspect for wasting/fasciculations

• Test tongue strength against cheek

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Emergency Red Flags

• Sudden visual loss

• Painful CN III palsy

• Multiple cranial nerve deficits

• Dysphagia or dysarthria

• New nystagmus with ataxia

• Progressive unilateral hearing loss

• Bilateral facial weakness

These require urgent imaging or senior review.

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Summary for the OSCE

Always close with a structured summary:

“This examination shows… [normal/abnormal findings].
I would complete a full neurological exam including motor, sensory, coordination, gait, and fundoscopy if indicated.
Based on these findings, my differentials include…
I would arrange the following investigations…”

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EMAM–Style Cranial Nerve Examination Script for MRCEM OSCE

Below is a polished, step-by-step script that you can speak out loud during an OSCE station.

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1. Introduction

“Hello, I’m Dr Mehdi. I’ve been asked to examine your cranial nerves, which control many head and neck functions.
This will involve checking your vision, facial movements, and some simple responses.
Is that okay? Great—I’ll wash my hands and begin.”

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2. General Inspection

“I’m looking for any obvious facial asymmetry, eyelid droop, abnormal eye position, or speech difficulty.”

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3. Cranial Nerve I – Olfactory

“This nerve controls smell; I won’t test it unless there is a specific concern.”

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4. Cranial Nerve II – Optic

Visual Acuity

“Do you wear glasses? Please keep them on.
Can you read the smallest line you can on this chart? Now cover your left eye… and now your right.”

Visual Fields

“Keep looking at my nose. Tell me when you see my finger wiggling.”
(Test all quadrants, each eye separately.)

Pupils

“I’m checking pupil size and shape.
I’m now shining a light to test direct and consensual reflexes.”
(Perform swinging light test if needed.)

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5. Cranial Nerves III, IV, VI – Eye Movements

“Please follow my finger with only your eyes.”
(Move finger in H-pattern.)
“Let me know if you see double at any point.”

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6. Cranial Nerve V – Trigeminal

Sensation

“I’m going to lightly touch your face; tell me if it feels the same on both sides.”
(Test V1, V2, V3.)

Motor

“Please clench your teeth—good… and now open your mouth.”

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7. Cranial Nerve VII – Facial

“Raise your eyebrows… close your eyes tightly—don’t let me open them.
Smile showing your teeth… now puff out your cheeks.”

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8. Cranial Nerve VIII – Vestibulocochlear

“I’m going to rub my fingers near each ear; tell me when you hear it.”
(Optional: whisper test.)
“Have you had any vertigo or balance problems?”

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9. Cranial Nerves IX & X – Glossopharyngeal & Vagus

“Say ‘ahh’ for me.”
“I’m checking the movement of your palate.
Your voice sounds normal.”

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10. Cranial Nerve XI – Accessory

“Shrug your shoulders against my hands…
Now turn your head left and right against my hand.”

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11. Cranial Nerve XII – Hypoglossal

“Stick out your tongue—I’m checking for deviation or wasting.
Please push your tongue into your cheek while I press from the outside.”

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12. Closing Summary

That completes the cranial nerve examination.
In summary… [state findings].
I would now proceed with a full neurological assessment, including motor, sensory, coordination and gait examination.”

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