Which cranial nerve is involved in formation of tympanic plexus-

Ans. is 'c' i.e., Glossopharyngeal nerve Tympanic plexus o Tympanic plexus is formed by i) Tympanic branch of glossopharyngeal nerve. ii) Superior and inferior caroticotympanic nerves which are branches of sympathetic plexus around internal carotid artery. o Tympanic plexus contains preganglionic secretomotor fibers which leave tympanic plexus via lesser petrosal nerve to relay in otic ganglion. Postganglionic fibers from otic ganglion supply parotid gland. o Tympanic plexus also innervates mucous membrane of middle ear, eustachian tube, and mastoid antrum and air cells.