Nerve · Head

Frontal nerve

Nervus frontalis

The largest of the three branches of the ophthalmic nerve, and the supply line for the forehead. It enters the eye socket through the superior orbital fissure above the ring of muscle origins and then does something unusual for a nerve of the orbit: it stays high, running forward just under the bony roof on the upper surface of the muscle that lifts the eyelid, and never touches the eyeball at all. About halfway along it divides into the supraorbital and supratrochlear nerves, which climb out over the brow. Everything you feel across your forehead and front scalp arrived through this single nerve. Note the name trap — the frontal BONE it runs beneath shares its name and nothing else.