Nasociliary nerve

The nasociliary nerve is the largest division of the ophthalmic nerve. It passes laterally to the optic nerve, then runs rostro-dorsally between the divisions of the muscle retractor bulbi to pass between the medial rectus muscle and the dorsal oblique muscle, tracing a curve towards the medial wall of the orbit. Shortly after entering the orbit, it gives rise to a communicating branch with ciliary ganglion and, shortly afterwards, the long ciliary nerves. It then splits into two terminal branches between the infratrochlear nerve and the ethmoidal nerve.