Examination of the cranial nerves

Though previously this page held a massive table of cranial nerve information "to simplify revision", it has been re-dedicated to the clinical examination of the cranial nerves. It therefore presents a summary of the steps taken to perform a thorough cranial nerve exam, and has greatest bearing for the hot cases of the CICM fellowship. In the SAQs one also frequently finds gaze palsies and cranial nerve signs.Given the college's tendency to ask about cranial nerve signs, familiarity with this material seems essential - its easy marks, and rapidly earned. Not to mention the enhancement of one's clinical abilities, and whatnot.

A short list of cranial nerve questions from the CICM written paper includes (but is not limited to ) the following:

The content below should be interpreted as stage instructions.
Alongside the examination manoeuvres, one can find links to the relevant chapters which deal with interpreting their findings.

Examination of the cranial nerves in the unconscious patient

• CN II and III: pupillary reflex
• CN V and VII: corneal reflex
• CN V:  painful stimulus over the orbit.
  • Observe the limbs. This may change your opinion of the GCS.
• CN VIII: oculocephalic or caloric reflex
  • The oculocephalic reflex will also tell you about CN III, IV and VI.
    Essentially, if the doll's eye is intact, then so is much of the brainstem.
• CN IX and X: gag reflex, cough reflex
  • Properly! get the tongue depressor in there and look with the neuro torch.
• CN XII, tongue fasciculation (generally seen while looking for the gag reflex)

Examination of the cranial nerves in the conscious patient

• CN I : block one nostril and ask the patient whether they can smell the opened alcohol swab.
• CN II: get the patient to read something convenient to grossly assess acuity (with each eye individually)
• Visual fields: its better to use the "count my fingers" technique
  • One should mention that without fundoscopy this stage of the cranial nerve examination is not complete. However, examiners may frown on somebody doing something that is not a part of routine ICU practice, so keep quiet about the fundoscopy.
• CN II and III: pupillary reflex
• CN II and III: accomodation
• Eye movements: "follow my finger", draw a broad H about 1m away from the patients face.
• CN V and VII: corneal reflex  (make sure the patient knows what is about to happen)
• CN V: facial sensation; light touch over the face - three regions: forehead, cheeks, chin.
• CN VII: facial movements: perform a few grimaces:
  • Raise eyebrows
  • Tightly close eyes; (try to force the eyelids open)
  • Puff out cheeks
  • Cheesy grin
  • Pout
• CN VIII: oculocephalic and cold caloric test - In the context of a long whole-day exam, one should probably avoid performing a caloric test in the awake exam patient, but one should mention that one wishes to do it. Otherwise, its Rinne's and Webers' tests, and who has a tuning fork nowadays?
• CN IX and X: gag reflex, cough reflex
  • Properly! get the tongue depressor in there and look with the neuro torch. Comment on the uvula. Ask them to say "Aaa" as this will cause the pharyngeal muscles to contract, dragging the uvula away from the lesion.
• CN XII: tongue movements:  get them to stick their tongue out and wiggle it from side to side.
• CN XI: get them to shrug their shoulders and turn their head left and right against your resistance.