Ophthalmic nerve

The ophthalmic nerve is the smallest division of the trigeminal nerve. It is a sensory nerve which supplies branches to the cornea, ciliary body and iris, lacrimal gland, conjunctiva, part of the mucosa of the nasal cavity and the skin of the eyelids, eyebrows, forehead and nose.

Initially united for a short distance with the maxillary nerve, it detaches at a very acute angle from the dorsomedial edge of the latter and enters the lateral wall of the cavernous sinus. In the latter, it is accompanied dorsomedially by the oculomotor and trochlear nerve and crossed ventrally by the abducent nerve. It reaches the orbital fissure or foramen orbitorotundum, where it divides into three terminal branches: frontal nerve, lacrimal and nasociliary, which together enter the orbit.