Lacrimal nerve

The lacrimal nerve is the smallest branch of the ophthalmic division of the trigeminal nerve (V1).

Gross anatomy

The lacrimal nerve divides off the ophthalmic division of the trigeminal nerve (V1) just before entering the orbit through the superior orbital fissure outside and superolateral to the tendinous ring. It is the most superior structure in the superior orbital fissure. It is the most lateral nerve that passes through the superior orbital fissure. As it enters the orbit, it courses laterally outside the cone of muscles beneath the periosteum of the orbital plate of the frontal bone (which it supplies) and along the superior margin of the lateral rectus muscle.

In the orbit it receives secretomotor parasympathetic fibers from the pterygopalatine ganglion via the zygomaticotemporal nerve (from the maxillary division of the trigeminal nerve) and sympathetic fibers from the adjacent lacrimal artery, which supply the lacrimal gland. It supplies the conjunctiva of the lateral upper eyelid and superior fornix. It then exits the orbit under the superior orbital margin laterally to supply the skin of the lateral forehead and scalp, lateral upper eyelid and around the lateral canthus.