Nerve of pterygoid canal

The nerve of pterygoid canal (a.k.a. Vidian nerve) is formed by the union of deep petrosal and greater petrosal nerves. It passes through the bony pterygoid canal which opens into the pterygopalatine fossa. Here, the nerve gets connected to the pterygopalatine ganglion.

The nerve of pterygoid canal provides autonomic neurons to the pterygopalatine ganglion. The autonomic neurons include the preganglionic parasympathetic fibers which arise from the facial nerve (superior salivatory) nucleus and reach the nerve of pterygoid canal through the greater petrosal nerve. Also included are the postganglionic sympathetic fibers, which come off from the plexus around the internal carotid artery as the deep petrosal nerve. The two petrosals join to form the nerve of pterygoid canal. Out of the two types of autonomic neurons, the pre-ganglionic parasympathetic neurons synapse inside the pterygopalatine ganglion, while the post-ganglionic sympathetic neurons simply traverse through the ganglion without relay.

Both sympathetic and parasympathetic fibers travel through various branches of the pterygopalatine ganglion to innervate different parts of the head and neck region. These branches include the greater palatine nerve (to the hard palate), lesser palatine nerve (to the soft palate, uvula and tonsils), pharyngeal nerve (to glands and mucosa of nasopharynx), nasal nerves (to nasal mucosa) and orbital nerve branches.

The autonomic sympathetic and parasympathetic fibers from the pterygopalatine ganglion reach the maxillary nerve through the ganglionic branches and get distributed along the branches of maxillary nerve to the lacrimal gland, nasal and oral cavities. These branches include the zygomatic nerve, posterior superior alveolar nerve, infraorbital nerve (and middle and anterior superior alveolar nerves).