Parasympathetic Ganglia of the Head

A schematic of the four parasympathetic ganglia of the head. Oculomotor fibres synapse in the ciliary ganglion; facial nerve fibres travel in the greater petrosal nerve to the pterygopalatine ganglion and in the chorda tympani to the submandibular ganglion; glossopharyngeal fibres in the lesser petrosal nerve synapse in the otic ganglion, which supplies the parotid through the auriculotemporal nerve.

This pathway is a reliable source of exam questions because it links several nerves in one chain. Candidates are expected to know which cranial nerve drives secretion from each gland: CN IX for the parotid, CN VII for the submandibular, sublingual, lacrimal and minor glands. It also explains Frey syndrome, in which parotid secretomotor fibres regrow into sweat glands after parotid surgery.