Lacrimal nerve

Lacrimal nerve is a branch of the ophthalmic division of the trigeminal nerve that provides sensory innervations for the lacrimal gland, conjunctiva and lateral upper eyelid of the respective side.

Course:

The lacrimal nerve passes forward in a separate tube of dura mater and enters the orbit through the upper narrowest part of the superior orbital fissure.

Within the orbit, it runs along the upper border of the lateral rectus muscle alongside the lacrimal artery. Here it is joined by a branch of the zygomaticotemporal nerve, which provides the parasympathetic secretomotor fibers for the gland.

The lacrimal nerve then enters the lacrimal gland and gives off many filaments that supply sensory innervation to the gland and the conjunctiva.

It then pierces the palpebral ligament (also known as the orbital septum) and ends by supplying the lateral part of the upper eyelid. It is here joined by filaments of the facial nerve.

Functions:

Lacrimal nerve provides sensory innervation for the lacrimal gland, conjunctiva and lateral part of the upper eyelid of the respective side.

The branch of zygomaticotemporal nerve (that joins lacrimal nerve in the orbital cavity), provides the parasympathetic secretomotor fibers.

Variations:

  • Sometimes, the lacrimal nerve also receives a branch from the trochlear nerve.
  • Sometimes, the lacrimal nerve is completely absent. Its place is taken by a branch of the zygomaticotemporal nerve.