| Tympanic nerve | |
|---|---|
 Plan of upper portions ofglossopharyngeal,vagus, andaccessory nerves. (Tympanic nerve visible in upper right) | |
 Tympanic nerve (labelled right side) | |
| Details | |
| To | Tympanic plexus |
| Identifiers | |
| Latin | nervus tympanicus |
| TA98 | A14.2.01.138 |
| TA2 | 6323 |
| FMA | 53480 |
| Anatomical terms of neuroanatomy | |
Thetympanic nerve (Jacobson's nerve) is a branch of theglossopharyngeal nerve passing through thepetrous part of the temporal bone to reach themiddle ear. It provides sensory innervation for the middle ear, theEustachian tube, theparotid gland, andmastoid cells. It also carriesparasympathetic fibers destined for the parotid gland.
The tympanic nerve contains sensory axons to themiddle ear (including the internal surface of thetympanic membrane) whose cell bodies are lodged in thesuperior ganglion of the glossopharyngeal nerve.[1][verification needed]
It also contains parasympathetic axons which continue as thelesser petrosal nerve to theotic ganglion, which itself gives off postganglionic parasympathetic neurons.[1][verification needed]
The tympanic nerve arises from theinferior ganglion of theglossopharyngeal nerve (CN IX)[1] in thejugular fossa.[2]
It passes through thepetrous part of the temporal bone within thetympanic canaliculus that is situated within the bony ridge separating thecarotid canal and thejugular foramen to reach themiddle ear.[2]
In thetympanic cavity of themiddle ear, it ramifies upon thepromontory of tympanic cavity to form thetympanic plexus.[2][1][verification needed]
The tympanic nerve provides sensation to themiddle ear (tympanic cavity).[1] This includes the internal surface of thetympanic membrane. It also supplies theEustachian tube, theparotid gland, andmastoid air cells.[1]
The tympanic nerve is also the parasympathetic root of theotic ganglion.[1][3] These neurons then provide secretomotor innervation of theparotid gland via theauriculotemporal nerve.[1] It is involved in the salivatory reflex to increasesalivation duringchewing.[4]
The tympanic nerve usually arises from theinferior ganglion of theglossopharyngeal nerve. Rarely, it may arise from a higher part.[1][verification needed] Rarely, it may provide no parasympathetic fibres to the otic ganglion.[3]
The tympanic nerve is involved in a reflex, where stimulation of theear canal increasessalivation.[4]
The tympanic nerve may be involved byparaganglioma, in this location referred to as a glomus tympanicum tumour.[5] This causes a soft mass in themiddle ear (tympanic cavity).[5] There may also bepulsatile tinnitus,hearing loss orhearing problems, and some cardiac abnormalities.[5]
The tympanic nerve is also known as the nerve of Jacobson, or Jacobson's nerve.[1]
This article incorporates text in thepublic domain frompage 910 of the 20th edition ofGray's Anatomy(1918)
