True about tympanic nerve:: (A) Is a branch of the facial nerve, (B) Contains postganglionic parasympathetic fibers, (C) Synapses with fibers in the lesser petrosal nerve, (D) Is a branch of the glossopharyngeal nerve
Answer is D. 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.