Parasympathetic root of otic ganglion; Lesser petrosal nerve
The lesser petrosal nerve (small superficial petrosal nerve) is the General visceral efferent (GVE) component of the glossopharyngeal nerve (CN IX), carrying parasympathetic fibers from the tympanic plexus to the parotid gland.
After arising in the tympanic plexus, the lesser petrosal nerve passes forward and then through the hiatus for lesser petrosal nerve on the anterior surface of the petrous part of the temporal bone into the middle cranial fossa. It travels across the floor of the middle cranial fossa, then exits the skull via foramen ovale to reach the infratemporal fossa. The fibres synapse in the otic ganglion, and post-ganglionic fibres then travel briefly with the auriculotemporal nerve (a branch of V3) before entering the body of the parotid gland.
The facial nerve gives off a branch at the geniculate ganglion for communication with the otic ganglion which joins the lesser petrosal nerve.