supratrochlear

Supratrochlear is an anatomical term describing structures located above the trochlea of the eye, particularly in the medial forehead region. It is used for both a nerve and an accompanying artery, and more generally to denote the region above the trochlea.

The supratrochlear nerve is a sensory branch of the frontal nerve, which in turn is a division of the ophthalmic branch (V1) of the trigeminal nerve. It ascends within the orbit and emerges on the forehead medial to the eyebrow, typically superior to the trochlea of the superior oblique muscle. The nerve provides cutaneous sensation to the middle part of the forehead and scalp up to the vertex, and it commonly travels with the supratrochlear artery.

The supratrochlear artery is a branch of the ophthalmic artery. It runs with the supratrochlear nerve toward the medial forehead, supplying cutaneous arteries of the medial forehead and contributing to an anastomotic network with the angular and supraorbital arteries.

Clinical significance includes regional anesthesia and surgical considerations. The supratrochlear nerve can be targeted for forehead nerve blocks in procedures involving the brow, eyelid, or anterior scalp. Injury or compression of this nerve or its accompanying vessels can cause numbness, paresthesia, or discomfort in the medial forehead. Anatomical variations in the exact course or exit point of the nerve and artery are possible, which can influence the approach to blocks or surgical planning.