Nerve · Head

Deep petrosal nerve

Nervus petrosus profundus

A purely sympathetic nerve, and the odd one out in a file of cranial nerve branches: it has no brainstem nucleus and belongs to no cranial nerve. Its fibres began in the upper thoracic spinal cord, relayed in the superior cervical ganglion in the neck, and then climbed into the skull as a plexus wound around the internal carotid artery. The deep petrosal nerve is the strand that leaves that plexus in the carotid canal, crosses the foramen lacerum, and joins the greater petrosal nerve to form the nerve of the pterygoid canal. Its fibres run straight through the pterygopalatine ganglion without relaying, ending on the blood vessels and glands of the nose, palate and tear gland.