These nerves have their superficial origin in the under surface of the cerebral peduncles. From this point they proceed in a forward direction, and enter the orbit through the foramen lacerum orbitale.

This nerve supplies the elevator muscle of the upper eyelid, the internal rectus, the superior and inferior rectus, the retractor oculi, and the small oblique muscle.

It also gives motor branches to the lenticular ganglion, and through it supplies the ciliary muscle and the circular fibres of the iris. It is essentially a motor nerve, and may cause all the parts named to contract.