<prompt> True about tympanic nerve:Is a branch of the facial nerveContains postganglionic parasympathetic fibersSynapses with fibers in the lesser petrosal nerveIs a branch of the glossopharyngeal nerve  <response>: The Tympanic nerve, or Jacobson nerve, is a branch of the Glossopharyngeal nerve. It contains preganglionic parasympathetic fibers, and forms a tympanic plexus on the medial wall of the middle ear with sympathetic fibers. The Tympanic nerve continues beyond the plexus as the Lesser petrosal nerve, which transmits preganglionic parasympathetic fibers to the otic ganglion for synapse. 