Oculomotor Nerve

This is the third (III) cranial nerve (CN). The origin of the nerve is a complicated nucleus termed the oculomotor nucleus, which is ventral to the cerebral aqueduct. The accessory oculomotor nucleus, including the Edinger-Westphal nucleus, also transverses through the red nucleus and becomes part of the oculomotor nerve. These nuclei are located in the midbrain. Each oculomotor nerve traverses between the posterior cerebral and superior cerebellar arteries and lateral to the posterior communicating artery in the interpeduncular subarachnoid cistern. From there, it runs through the arachnoid and dura mater and enters the roof of the cavernous sinus. It runs above CN IV and then divides into the superior and inferior rami as it enters the orbit through the superior orbital fissure. The superior division has branches to the superior rectus muscle and to the main superficial lamina of the levator palpebrae superioris. The inferior division, which is larger than superior division,...