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What is Presence of aneurysm in the posterior communicating aery cause compression of which of the following cranial nerve? and explain in detail?
Oculomotor travels alongside the posterior communicating aery as it moves towards the cavernous sinus. Therefore aneurysm of the posterior communicating aery cause compression of the third nerve. This leads to isolated third nerve paresis with pupil getting involved. Uncal herniation across the tentorial edge cause compression of the third nerve. This leads to dilated and fixed pupil called Hutchinson pupil. It is the first indication that altered consciousness is due to a space occupying lesion. Ref: Textbook of Ophthalmology edited by Sunita Agarwa page 333.