Corpus: Supratrochlear nerve

The supratrochlear nerve is the smaller of the two branches of the frontal nerve.

The supratrochlear nerve branches off from the frontal nerve midway between the apex and the edge of the eye socket. Above the trochlea of the superior oblique muscle, it sends some nerve fibers to the infratrochlear branch of the nasociliary nerve.

It then exits the orbit between the trochlea and the orbital rim by piercing the orbital septum below the frontal notch. It ascends to the forehead, passing between the corrugator supercilii muscle and the occipitofrontal muscle. Its branches pierce these muscles and provide sensory innervation to the skin of the lower forehead and the upper eyelid.