Nerve · Head

Ophthalmic nerve

Nervus ophthalmicus

The first and smallest of the three divisions of the trigeminal nerve, and the one that serves the eye and the forehead. It is purely sensory — it moves nothing — and it carries feeling from the cornea, the upper eyelid, the bridge and tip of the nose, the forehead and the scalp as far back as the crown of the head. It runs forward inside the wall of the cavernous sinus and splits into three named branches (lacrimal, frontal, nasociliary) that enter the eye socket through the superior orbital fissure. Its distinguishing job is the cornea: touch the surface of the eye and it is this nerve that reports it, which makes it the sensing half of the blink reflex.