Examination: Cranial Nerves
The cranial nerve examination has the most complicated structures of all the physical examinations as it is based on the anatomical sequence of cranial nerves, rather than function. Therefore, it is vital that you know the correct sequence, names, and functions of the cranial nerves BEFORE embarking on trying to master this examination.
We have tried to represent a comprehensive cranial nerve examination, though the technique involved in these actions requires demonstration by an experienced clinician, and lots of practice. If you have any good online resources (videos/diagrams/tutorials) for any of specific points below then please post them as a comment at the bottom!
- 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
- Ensure you have the correct equipment: cotton wool, 512Hz tuning fork, tendon hammer, pen torch (plus optional: Snellen chart, Ishihara plates, ophthalmoscope)
- You should sit down opposite them so you are both at eye level with each other.
- Inspect patient as a whole first, looking for any obvious abnormalities, such as a facial droop or ptosis
- Then proceed to examine the patient's cranial nerves individually, as below;
Ask the patient whether they have noticed any change in their sense of smell recently?
You can test this nerve objectively by testing each nostril individually with coffee. Do NOT offer to use ammonia to test the Olfactory nerve as noxious smells will also stimulate the Trigeminal nerve.
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. Look at movements of eyes - are they able to look in all directions? Ask if patient can see double or if vision is blurred at any point during the test (this indicates inadequate visual alignment).
To 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. Do they show nystagmus? 2-3 beats is acceptable; more than this indicates pathology. Carry out the reverse (right to left) movement. Also, do they have nystagmus movements when focusing in the centre of their visual field (this is normally pathological)?
Test sensation first
Then test motor system:
Ask patient to do the following (unopposed, and then against resistance), and check for symmetry:
Then ask them to smile and show their teeth.
'Screening' - rub fingers together by one ear, and whisper a two-digit number (e.g. 72) by the other. Ask the patient to repeat the number back to you. This is obviously dependent on how softly you whisper.
Specific tests (using a 512Hz tuning fork): Weber's Test and Rinne's Test (see Ear Examination for details)
Ask the patient to shrug their shoulders, and then resist your attempts to push their shoulders down. Is this symmetrical?
Put your flat palm on one side of the patient's face and ask them to turn their head against your hand. Is this symmetrical?
Ask the patient to open their mouth wide:
- Thank the patient and wash your hands
- Turn to the examiner and explain that you would like to finish your examination by: