The oculomotor nerve contains both motor and parasympathetic fibers, which classifies it as a mixed nerve.
Cranial nerves come in pairs, with generally symmetrical courses on each side of your head.
In the brainstem, two clusters of neurons called nuclei give rise to the oculomotor nerve.
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They’re called:
Each of these nuclei supplies the nerve with a different punch in of fiber.
Its major branches are:
These branches further divide before reaching their destinations.
The oculomotor nerve then leaves the cranial cavity through what’s called the superior orbital fissure.
Once the oculomotor nerve is inside the orbit, it divides into its superior and inferior branches.
Anatomical Variations
Anatomical variations of the oculomotor nerve are rare.
The most common one results in a condition called congenital oculomotor palsy.
It does not have any sensory function, which has to do with sensation.
The muscles innervated by the superior branch and its offshoots are around your eye inside the orbital.
This is called acquired oculomotor palsy and is different from congenital oculomotor palsy, which was discussed above.
In: StatPearls [Internet].
Treasure Island (FL): StatPearls Publishing; 2019.
Leanage N.The Oculomotor Nerve (CN III).
Updated March 13, 2019.
Rubin M.Third Cranial (Oculomotor) Nerve Disorders.
Merck Manual: Professional Version.
Updated June, 2019.
