Structure and Origin
- The tympanic nerve contains sensory axons to the middle ear, including the internal surface of the tympanic membrane.
- Cell bodies of these sensory axons are located in the superior ganglion of the glossopharyngeal nerve.
- It also contains parasympathetic axons that continue as the lesser petrosal nerve to the otic ganglion.
- The otic ganglion gives off postganglionic parasympathetic neurons.
- The tympanic nerve arises from the inferior ganglion of the glossopharyngeal nerve (CN IX).
- The origin is in the jugular fossa.
Course
- The tympanic nerve passes through the petrous part of the temporal bone within the tympanic canaliculus.
- The canaliculus is situated within the bony ridge separating the carotid canal and the jugular foramen.
- It reaches the middle ear through this course.
- In the tympanic cavity of the middle ear, it ramifies upon the promontory of the tympanic cavity.
- This forms the tympanic plexus.
Sensory Distribution
- The tympanic nerve provides sensation to the middle ear (tympanic cavity).
- It also supplies the internal surface of the tympanic membrane, Eustachian tube, parotid gland, and mastoid air cells.
Parasympathetic Autonomic Distribution
- The tympanic nerve is the parasympathetic root of the otic ganglion.
- The otic ganglion provides secretomotor innervation of the parotid gland via the auriculotemporal nerve.
- It is involved in the salivatory reflex to increase salivation during chewing.
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 fibers to the otic ganglion.
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 nerve | |
|---|---|
 Plan of upper portions of glossopharyngeal, vagus, and accessory 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 | |
tympanic nerve (plural tympanic nerves)
