The eye is deviated downwards and outwards.
There is ptosis.
The pupil is dilated, indicating that there is parasympathetic damage (= a 'surgical' third nerve palsy)/ the pupil is not dilated, indicating no parasympathetic damage (= a 'medical' third nerve palsy)
There is ptosis.
The pupil is dilated, indicating that there is parasympathetic damage (= a 'surgical' third nerve palsy)/ the pupil is not dilated, indicating no parasympathetic damage (= a 'medical' third nerve palsy)
Quick recap of the muscles of eye movement:
What causes of a 'medical' third nerve palsy do you know?
- mononeuritis multiplex - classically diabetes
- MS
- midbrain infarction
- migraine
What causes of a 'surgical' third nerve palsy do you know?
- cavernous sinus pathology - thrombosis, fistula, infiltrative conditions like Wegeners or sarcoidosis
- posterior communicating artery aneurysm (classically painful)
