The ophthalmic nerve is composed of sensory fibers. It is one of the three branches of Cranial Nerve V (trigeminal nerve). The ophthalmic nerve travels through the wall of the cavernous sinus, entering the orbit via the superior orbital fissure. Once in the orbit, the Ophthalmic nerve branches into the nasociliary nerve, the lacrimal nerve, and the frontal nerve. The nasociliary nerve serves the mucosal lining of part of the nasal cavity, the tentorium cerebelli and some of the dura mater. The lacrimal nerve serves the lacrimal gland, part of the upper eyelid, and the conjunctiva. The frontal nerve branches into the supratrochlear nerve and the supraorbital nerve.