Educational objective: The third cranial nerve (oculomotor) ca | Embryology Videos & Books 2021

Educational objective: The third cranial nerve (oculomotor) carrying general somatic efferent fiber and general visceral efferent parasympathetic fiber exits the midbrain and courses between the posterior cerebral and superior cerebellar arteries. An aneurysm arising from either artery can lead to a non-pupil-sparing third nerve palsy, which clinically presents with unilateral headache, eye pain, diplopia, dilated nonreactive pupil, and ptosis with the ipsilateral eye in a down and out position.