Lacrimal nerve
The lacrimal nerve is the smallest of the three main branches of the ophthalmic nerve (CN V1).
It enters the orbit outside the common tendinous ring and passes forward along the side wall of the orbit.
It provides sensory innervation to the skin and both surfaces of conjunctiva at the lateral portion of the upper eyelid.
It also receives a parasympathetic secretomotor communicating branch for the lacrimal gland which it conveys to the gland.
Structure
Origin
The lacrimal nerve branches from the ophthalmic nerve immediately before traveling through the superior orbital fissure to enter the orbit.At the superior portion of the lateral wall of the orbit, it also receives a secretomotor' communicating' parasympathetic branch from the zygomaticotemporal nerve for the lacrimal gland.''''''
Course
It enters the orbit through the superior orbital fissure outside the common tendinous ring, coursing lateral to the frontal nerve and trochlear nerve (CN IV). Once inside the orbit, it travels anteriorly along the lateral wall of the orbit upon the superior margin of the lateral rectus muscle;' here, it receives a secretomotor branch for the lacrimal gland from the zygomaticotemporal nerve.' It is accompanied by the lacrimal artery along its course through the orbit. It travels through the lacrimal gland, supplying the gland with sensory and parasympathetic branches, then continuing anteriorly as a few small sensory branches. It pierces the orbital septum to reach its terminal target tissues.''''''Distribution
Sensory
The lacrimal nerve provides sensory innervation to:- the lacrimal gland
- a small area of' skin over the lateral portion of the upper eyelid'
- both surfaces of the conjunctiva at the lateral portion of the upper eyelid
- skin of the lateral forehead and scalp.