Nerve · Head

Infratrochlear nerve

Nervus infratrochlearis

A small terminal branch of the nasociliary nerve serving the inner corner of the eye. It runs forward along the upper border of the medial rectus muscle and leaves the orbit BELOW the trochlea — directly under the path its near-namesake the supratrochlear nerve takes above it, which is the whole of the difference between the two names. It supplies the skin of both eyelids near the nose, the lacrimal sac, the caruncle (the pink fleshy bump at the inner corner) and the side of the root of the nose. It is the reason the inner corner of the eye and the top of the nose feel like one place rather than two.