Nerve · Head

Anterior ethmoidal nerve

Nervus ethmoidalis anterior

The terminal continuation of the nasociliary nerve, and the sensory supply of the front of the nose inside and out. Its route is the strangest of any nerve of the face: it leaves the eye socket through the anterior ethmoidal canal, crosses briefly over the roof of the nose INSIDE the cranial cavity beside the crista galli, then drops back down through a slit in the cribriform plate into the nasal cavity — a nerve that passes through the floor of the brain's front chamber to travel a few centimetres sideways. It supplies the lining of the upper front of the nose, then emerges between the nasal bone and the cartilage below it as the external nasal nerve, to the skin of the lower half of the nose and its tip.