Trochlear nerve

The trochlear nerve, also called the fourth cranial nerve or CN IV, is a motor nerve (a somatic efferent nerve) that innervates only a single muscle: the superior oblique muscle of the eye, which operates through the pulley-like trochlea.Dura mater and its processes exposed by removing part of the right half of the skull, and the brain.Hind- and mid-brains; postero-lateral view.Dissection showing origins of right ocular muscles, and nerves entering by the superior orbital fissure.Upper part of medulla spinalis and hind- and mid-brains; posterior aspect, exposed in situ.Trochlear nerve.Deep dissection.Superior view. The trochlear nerve, also called the fourth cranial nerve or CN IV, is a motor nerve (a somatic efferent nerve) that innervates only a single muscle: the superior oblique muscle of the eye, which operates through the pulley-like trochlea.