TYMPANIC PLEXUS

A plexus on the promontory of the labyrinthine wall of the tympanic cavity, formed by the tympanic nerve, an anastomotic branch of the facial, and sympathetic divisions from the inside carotid plexus; it supplies the mucosa of the medium ear, mastoid cells, and auditory (eustachian) pipe, and gives off the petrosal nerve' >lesser superficial petrosal nerve to the otic ganglion. Synonym: plexus tympanicus, Jacobson's plexus.