tympanic plexus
n.
A plexus that is located on the promontory of the labyrinthine wall of the tympanic cavity, is formed by the tympanic nerve, by an anastomotic branch of the facial nerve, and by sympathetic branches coming from the internal carotid plexus, supplies the mucosa of the middle ear, the mastoid cells, and the auditory tube, and gives off the lesser petrosal nerve to the otic ganglion.