tympanic nerve tympanic nerve the tympanic nerve (jacobson’s nerve) is a branch of the glossopharyngeal nerve found near the ear. it gives sensation to the middle ear, the eustachian tube, the parotid gland, and mastoid air cells. it gives parasympathetic to supply to the parotid gland via the otic ganglion and the auriculotemporal nerve. tympanic nerveplan of upper portions of glossopharyngeal, vagus, and accessory nerves. (tympanic nerve visible in upper right)tympanic nerve (labelled right side)detailstotympanic plexusidentifierslatinnervus tympanicusta98a14.2.01.138ta26323fma53480anatomical terms of neuroanatomy structure the tympanic nerve arises from the inferior ganglion of the glossopharyngeal nerve. it ascends to the tympanic cavity through a small canal, the inferior tympanic canaliculus, on the under surface of the petrous portion of the temporal bone on the ridge which separates the carotid canal from the jugular fossa. in the tympanic cavity, it divides into branches which form the tympanic plexus and are contained in grooves upon the surface of the promontory. the tympanic nerve contains sensory axons to the middle ear, including the internal surface of the tympanic membrane. their cell bodies are found in the superior ganglion of the glossopharyngeal nerve. it also contains parasympathetic axons, which continue as the lesser petrosal nerve to the otic ganglion, which itself gives off postganglionic parasympathetic neurons. variation the tympanic nerve usually arises from the inferior ganglion of the glossopharyngeal nerve. rarely, it may arise from a higher part. rarely, it may provide no parasympathetic fibres to the otic ganglion. function the tympanic nerve provides sensation to the middle ear (tympanic cavity). this includes the internal surface of the tympanic membrane. it also supplies the eustachian tube, the parotid gland, and mastoid air cells. the tympanic nerve also gives parasympathetic supply to the otic ganglion. these neurons then provide secretomotor innervation of the parotid gland via the auriculotemporal nerve. it is involved in the salivatory reflex to increase salivation during chewing. clinical significance the tympanic nerve is involved in a reflex, where stimulation of the ear canal increases salivation. cancer the tympanic nerve may be involved by paraganglioma, in this location referred to as a glomus tympanicum tumour. this causes a soft mass in the middle ear (tympanic cavity). there may also be pulsatile tinnitus, hearing loss or hearing problems, and some cardiac abnormalities. history the tympanic nerve is also known as the nerve of jacobson, or jacobson's nerve. additional images lesser petrosal nerve sympathetic connections of the otic and superior cervical ganglia.