Cranial Nerve Exam 1 Step by step examination

Cranial Nerve Exam 1. Step by step examination taking you through each individual nerve 2. Common OSCE questions for a cranial nerve station 3. Video by geeky medics showing you how its done NB: OSCE scenario for your year. You’d probably only be asked to do CNI-VI or from CNVII-XII. Sammy Sharif. 4 th year.

WIPEE Wash hands Introduce yourself Gain Permission Explain the examination Expose pt – the pt in the osce will be adequately exposed. Hi, I’m Sammy Sharif, a 4 th year medical student. Today I’ve been asked to perform an examination of your nerves in your head and neck. Is that ok? Ok great, this will just involve me having a look at your vision and eye movements, testing some of the muscles on your face and testing your sensation.

General Inspection Ptosis/exophthalmos Facial symmetry Wasting of sternocleidomastoid Speech CNI: Olfactory “Have you noticed any change in your sense of smell” If examiner asks how you would test (very unlikely): Say you would cover each nostril, ask pt close their eyes and smell something strong like coffee or peppermint.

CNII: Optic REMEMBER THIS GUY!! Just remember AFRO A: Acuity. Ask pt if they wear glasses/contacts – make sure they’re in/on. Cover one eye. Stand 6 m away (or say you would stand 6 m away) with snellen chart and ask pt which line is the lowest they can read. Then cover other eye and repeat. 6/12 vision = ptcan read at 6 m what a healthy eye can read at 12 m. F: Fields. (Hard to explain so I’ll show you). Sit opposite patient. Cover your left eye with your left hand. Ask patient to cover their right eye with their right hand. Wiggle your fingers in the 2 quadrants related to your right eye equidistant between you and slowly bring them towards the middle. Ask pt when they can see them wiggling. They should see them wiggling the same time you do. Then keep covering your same eye but with your right hand this time to allow you to wiggle your fingers in the 2 quadrants on your left. After 4 quadrants, pt covers their other eye and repeat process.

R: Reflexes. 3 to remember: o Pupillary reflex: shine light in one eye – observe for direct response (same pupil constricts). Then take light away and re-shine it in same eye. Observe for consensual response (other pupil should constrict). (If you want to be a boss, then perform swinging flash light test to test for reactive afferent pupillary defect) o Corneal Reflex: Just say you would do it with a wisp of cotton wool. Don’t do it in the OSCE. o Accommodation reflex: Ask pt to stare at your finger and follow it as you bring it close towards their nose. Eyes should converge onto it. o NB: Pupillary light and accommodation reflex: afferent arm is optic nerve, efferent arm is the occulomotor, trochlear, abducens. Test them all here because its easier to keep all reflexes together O: Ophthalmoscopy: Just state that you would perform ophthalmoscopy/fundoscopy. They wouldn’t expect you to do it. It’s a whole separate station.

CNIII, IV, VI: Occulomotor, Trochlear, Abducens Ask pt to keep their head straight and look at your finger with their eyes only. Make a H pattern and watch their eyes follow it. Ask if there any pain or double vision while doing that. Test for nystagmus. Slow movement of your finger to one side then fast movement back the other way. Can do it vertically too if you wish. CNV: Trigeminal Muscles of mastication. Ask pt to clench their jaw. Feel their masseter and temporalis muscle bulk. Ask pt to open jaw against your resistance. Sensation: show them how it feels on their sternum, Use cotton wool. Test in the ophthalmic, maxillary and mandibular areas. COMPARE BOTH SIDES. Offer the examiner to do pain and temperature sensation + and the jaw jerk reflex.

CNVII: Facial Just remember the branches and test in that order: • To Zanzibar By Motor Car • Temporal, Zygomatic, Buccal, Mandibular, Cervical. • Temporal: Raise your eyebrows • Zygomatic: Scrunch up your eyes • Buccal: Blow out your cheeks • Mandibular: Whistle • Cervical: Stick forward your chin as if you were shaving.

CNVIII: Vestibulocochlear Obscure one ear canal by rubbing on tragus. Whisper a number into the other ear an arm’s length away and ask them to repeat it. Then same for other ear. Rinne’s and Weber’s (So many variations): o Rinne’s always done first. Make a 512 Hz tuning fork buzz. Place the bottom onto the mastoid process (tell pt this is position 1). Then place the two prongs in front of the ear (tell pt this is position 2). Ask pt which position they heard it loudest o Interpretation of Rinne’s: v Normal hearing or Sensorineural hearing loss: Air conduction is better than bone conduction. This is termed Rinne’s positive. v Conductive Hearing loss: Bone conduction is better than air conduction. Rinne’s negative o Weber’s: Make tuning fork buzz. Place bottom on the top of the head in the middle. Ask pt which ear they hear it loudest or is it both the same o Interpretation of Weber’s v Normal: sound heard equally in both ears v Sensorineural hearing loss: sound loudest in normal ear v Conductive hearing loss: sound loudest in affected ear

Example: Pt has conductive hearing loss in right ear. What will Rinne’s and Weber’s show? Bone conduction will be better than air conduction when performing Rinne’s on the right ear. Therefore Rinne’s is negative. Sound will lateralize to the right ear when performing Weber’s. Pt has sensorineural hearing loss in right ear. What will Rinne’s and Weber’s show? Air conduction will be better than bone conduction when performing Rinne’s on the right ear. Air conduction will also be better than bone conduction on the left ear. You would think everything is normal (two positive Rinne’s tests). But when you do Weber’s - sound will lateralize to the left ear.

CNIX + X: glossopharyngeal + vagus Ask pt to cough Ask pt to sip some water Ask pt to say AAH – look for uvula deviation – uvula deviates to unaffected side. Offer gag reflex CNXI: Spinal Accessory Shrug shoulders against resistance Move head right and then left both against resistance CNXII: Hypoglossal Ask pt to open their mouth and poke their tongue out. Look for any fasciculations/deviations. If deviated to the right, right hypoglossal nerve affected.

Common Q’s A VIth nerve palsy prevents the eye from doing what movement? Abduction What are the characteristic symptoms of a headache due to raised ICP? • At their worst first thing in the morning. • Worse on Valsalva (coughing, sneezing, pooing). • Accompanied with other signs: vomiting, drowsiness, vision changes. How would you differentiate between an upper motor neuron VII lesion from a lower motor neuron VII lesion? UMN lesion: there is forehead sparing i. e pt would still be able to raise both eyebrows.

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