OSCE-Aid Revision Workshops: Cranial Nerves
Cranial Nerve Examination
Overview:
This is a role-play exercise based on a typical short OSCE examination station. In this
scenario, the student will be given ten minutes to examine a patient’s cranial nerves. In any
OSCE, a student may be asked to examine all or part of the cranial nerves I – XII in this
time.
Format of the exercise:
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Ask one student to be the actor and one to be the OSCE finalist.
Provide the actor with their brief and the student with the scenario instructions (both
overleaf).
Ask the student to read the instructions to the group. Check for questions.
The student should proceed to manage the actor – allow 8 minutes for examination
and 2 minutes to summarise/ask questions below
The examiner should only volunteer answers to specific questions as detailed below
and should provide examination and investigation findings when specifically asked by
the student.
Afterwards, gather feedback. Start with the student then open it up to the group.
Then provide your own feedback to the student.
Finally, discuss key learning points. Suggestions for questions to ask the group, a
recommended ‘model answer’ and key discussion points are included overleaf.
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OSCE-Aid Revision Workshops: Cranial Nerves
Student instructions
To be read out loud by the student to the group
Please examine this patient’s cranial nerves. Do not take a history. Offer to do all aspects of
the examination; the examiner will tell you to move on if not needed and answer your
questions with findings.
You have 9 minutes to examine the patient and 1 minute to discuss with the examiner at the
end.
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OSCE-Aid Revision Workshops: Cranial Nerves
Actor’s brief
On examination: there are no abnormalities.
Only volunteer specific information about symptoms and your past medical history when
asked the relevant and specific questions by the student. If any questions cannot be
answered with the above information, please answer “no” or “don’t know”.
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OSCE-Aid Revision Workshops: Cranial Nerves
Model examination/instructions for examiner
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Wash your hands
Introduce yourself
Tell the patient that you would like to examine the nerves in their head and neck
Ask if they are happy to do this
Reposition the patient sitting down
I – Olfactory – offer to do this, move student on
II – Optic
◦ Visual acuity – offer to do this, move student on
◦ Colour recognition – offer to do this, move student on
◦ Fundoscopy – offer to do this, move student on
◦ Pupillary reflexes –
A) LIGHT
- check for pupil symmetry
- check for ipsilateral (same side) and contralateral (opposite side) pupil
constriction
- Test for relative afferent pupillary defect (RAPD)
B) ACCOMODATION
- ask the patient to focus on a distant spot, then change focus to your finger
(15cm in front of their face). Their pupil should constrict to focus.
◦ Convergence - "look at a distant object, now look at my finger"
◦ Visual fields:
A) Visual neglect: ask the patient to keep both eyes open. Hold your hands at the
periphery of their vision and wave each hand in turn each time asking the patient
to state which hand is waving. Then wave both hands. B) Cover one of your own eyes and ask the patient to cover the mirror eye and fix
their gaze on your nose, keeping their head still. Hold one of your fingers in the
upper outer quadrant of their visual field and move it towards the centre asking
the patient to identify the point at which they first see the finger/pin. Repeat this
for the other 3 quadrants and then repeat with the other eye. C) Offer to assess blind spot – move on
III – Oculomotor/ IV – Trochlear/ VI - Abducens
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Test all three nerves together: move finger in a large 'H' shape across the patient's
field of vision and ask patient to follow finger whilst keeping their head still. Ask if
patient can see double or if vision is blurred at any point during the test
Test for nystagmus: ask the patient to focus on the tip of your finger. Hold your finger
at the left lateral edge of their visual field, and move it rapidly to the right lateral edge
of their visual field and hold it there. 2-3 beats is acceptable; more than this indicates
pathology. Carry out the reverse (right to left) movement.
V – Trigeminal
◦ Sensation:
- Test sensation on the sternum with cotton wool
first
- Press (don't rub) the cotton wool in the
distribution of the ophthalmic (forehead), maxillary
(cheek) and mandibular (jaw) divisions
- Test like for like bilaterally and ask them if it
feels the same on both sides
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OSCE-Aid Revision Workshops: Cranial Nerves
◦ Motor:
- Corneal reflex - offer to do this, move student on
- Jaw jerk reflex - offer to do this, move student on
- Ask patient to clench their jaw - feel temporalis and masseter muscles for contraction
- Open jaw to resistance (try to push their jaw up).
VII – Facial
- Inspect: comment on facial symmetry/appearance
- Assess taste - move student on
- Raise their eyebrows
- Close their eyes tightly
- Hold their lips together and blow out their cheeks
VIII – Vestibulocochlear
- Rub fingers together by one ear, and whisper a two-digit number (e.g. 72) by the
other
- Offer to carry out specific tests Weber's Test and Rinne's Test - move student on
IX – Glossopharyngeal/ X - Vagus
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Ask the patient to open their mouth and say 'ahh' - look at uvula
Examine the gag reflex (with an orange stick) – offer to do this, move student on
Assess the patient's swallow - offer to do this, move student on
XI – Accessory
- Ask the patient to shrug their shoulders + resist your attempts to push their shoulders
down
- Put your flat palm on one side of the patient's face and ask them to turn their head
against your hand. Feel for sternocleidomastoid strength
XII – Hypoglossal
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Inspect the tongue for fasciculations at rest
Ask the patient to stick out their tongue straight and check for deviation
Ask the patient to move their tongue from side to side
Questions to ask student
1. Please summarise your findings - normal findings
2. How would you complete your examination? – assess speech, swallow, take a full
history, full neurological examination, fundoscopy
3. What investigations/tests you would you like to order – consider CT head or MRI
brain, bloods
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OSCE-Aid Revision Workshops: Cranial Nerves
Key learning points for students on cranial nerve palsies:
Group discussion around common cranial nerve pathologies (this should be useful for osces
but also for writtens) – images on pages below
Questions for group:
CRN 3 PALSY – show students PICTURE A
1. What abnormality on the left of the page?
2. Where is the site of the lesion? Partial or total? Consider using clip board for this
3. Causes for 3rd nerve palsy?
4. This is a partial nerve palsy - would you expect this finding in all causes of 3rd nerve
palsy?
5. What questions would you want to ask patient? Tell student that patient is a type 1
diabetic – what other neurological findings would you expect?
VISUAL FIELD DEFECTS – show students PICTURE C
1. Where are the sites of lesions?
2. Revision of optic pathway
3. Causes of lesions along pathway (see below) – encourage students to write in
causes as go through handout and sites of lesions
BELL’S PALSY – show students PICTURE B
1. What is this?
2. How do you distinguish between this and an UMN lesion?
BULBAR PALSY
1. What is this?
2. How do you distinguish between this and an UMN (pseudobulbar) lesion?
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OSCE-Aid Revision Workshops: Cranial Nerves
Answers for group/general points:
Questions to consider in cranial nerves examination:
1. Single cranial nerve or groups of cranial nerves?
2. Where is the site of the lesion? In brainstem or outside brainstem?
Common pathologies: Please review with above questions
1. Crn 3 palsy:
Findings:
1. Partial or full ptosis
2. Eye down and out
3. Pupils may be equal and reactive to light or fixed and dilated one affected
side
4. Convergence will be impaired
Causes:
1. ‘Medical’ causes: diabetes, atherosclerosis, inflammation, infection,
demyelinating disease egg multiple sclerosis  usually partial 3rd nerve
palsy
2. ‘Surgical’ causes: aneurysms egg posterior communicating artery,
SOLs/tumours, trauma, cavernous sinus thrombosis  usually total 3rd
nerve palsy
Other neurological findings if patient was a type 1 diabetic:
1. Diabetic feet e.g.: peripheral neuropathy, charcot joint, ulcers
2. Diabetic gastroparesis/other autonomic neuropathy
3. Fundoscopy – proliferative or non-proliferative diabetic retinopathy
Causes of ptosis:
 Bilateral: myasthenia gravis, myotonic dystrophy
 Unilateral: 3rd nerve palsy, horner’s syndrome
2. Visual field defects:
a. Bitemporal hemianopia – loss of temporal fields bilaterally, all other fields
intact. Causes: compression at optic chiasm e.g.: pituitary adenoma,
craniopharyngioma, internal carotid artery aneurysm
b. Monocular blindness – lesion at eye or optic nerve. Causes: eye pathology,
MS, GCA
c. Homonymous hemianopia or quadrantanopia – loss of L or R-sided fields or
quadrants contralateral to lesion in each eye. Lesion beyond optic chiasm, at
level of tracts, radiation, or occipital cortex. Causes: stroke, SOL, abscess,
inflammatory process e.g.: abscess
3. Facial nerve palsy:
a. LMN: unilateral flaccid facial weakness, unable to raise eyebrows. Causes:
Bell’s palsy, skull fracture, CPA tumours, Lyme disease, Ramsay Hunt
syndrome, sarcoidosis, diabetes
b. UMN: spares forehead, able to raise eyebrows. Causes: stroke, tumour
4. Lower cranial nerve findings:
a. Bulbar palsy: diseases of nuclei of cranial nerves IX-XII in medulla - LMN.
i. Signs: flaccid, fasciculating tongue, jaw jerk absent, speech is
quiet/hoarse/nasal.
ii. Causes: MND, GBS, polio, myasthenia gravis, syringobulbia,
brainstem tumours, central pontine myelinolysis
b. Pseudobulbar palsy: UMN lesion due to lesions of corticobulbar tracts
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OSCE-Aid Revision Workshops: Cranial Nerves
i. Signs: slow tongue movements, slow speech, hyperreflexic jaw jerk,
emotional lability
ii. Causes: MS, MND, stroke, central pontine myelinolysis
5. Groupings of cranial nerves:
a. V, VI, VIII, IX, X: CPA lesions/tumours egg acoustic neuroma
b. V, VI: lesion at apex of petrous temporal bone egg complication of otitis
media
c. III, IV, VI: stroke, tumours, Wernicke’s encephalopathy, aneurysms, MS
d. III, IV, Va, VI: cavernous sinus thrombosis, superior orbital fissure lesions
e. IX, X, XI: jugular foramen lesion
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