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Neurology / OSCE

Cranial Nerves OSCE Guide

Quick bedside tests for each cranial nerve, plus the mnemonics that make the names and functions stick.

Quick Tests by Nerve

NerveFunctionQuick test
I — OlfactorySmellIdentify a scent with eyes closed
II — OpticVisionVisual acuity, visual fields, pupillary light reflex
III, IV, VIEye movementFollow finger in H-pattern; pupil size and symmetry
V — TrigeminalFacial sensation, jawLight touch in 3 divisions; clench jaw; corneal reflex
VII — FacialFacial movementRaise eyebrows, close eyes tightly, smile, puff cheeks
VIII — VestibulocochlearHearing, balanceWhisper test; Rinne and Weber tests
IX, XSwallow, gag, voiceGag reflex, palate movement, say "ah," swallow
XI — AccessoryShoulder, neckShrug shoulders, turn head against resistance
XII — HypoglossalTongue movementProtrude tongue, check for deviation

Mnemonics

To remember the names, in order (I-XII):
"Oh, Oh, Oh, To Touch And Feel Very Good Velvet, Ah Heaven" — Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal.

To remember whether each is Sensory, Motor, or Both:
"Some Say Marry Money, But My Brother Says Big Brains Matter More" — S, S, M, M, B, M, B, S, B, B, M, M.

Common Pitfalls

For the full physical exam sequence and opening/closing checklist, see the OSCE Cheat Sheets page.

Frequently Asked Questions

Which cranial nerve tests double as a brainstem check?

The pupillary light reflex (CN II afferent, CN III efferent) and the corneal reflex (CN V afferent, CN VII efferent) are both used to assess brainstem function in unconscious patients.

Do I need special equipment to test cranial nerves?

Most tests need only a pen torch, a wisp of cotton wool, something to smell (optional), and a tuning fork for Rinne/Weber — no specialized equipment is required for a screening exam.

What does tongue deviation on protrusion indicate?

In a lower motor neuron CN XII lesion, the tongue deviates toward the side of the lesion (the weak side) on protrusion.