Tympanic nerve (labelled right side)
|Anatomical terms of neuroanatomy|
The tympanic nerve (nerve of Jacobson) is a branch of the glossopharyngeal nerve found near the ear.
It arises from the petrous ganglion, and 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.
Jacobson's nerve contains both sensory and secretory fibers.
- Sensory fibers supply the middle ear.
- Parasympathetic secretory fibers continue as the Lesser Petrosal nerve and provide secretomotor innervation to the parotid gland. The secretory fibers enter the otic ganglion.
- Sympathetic fibers (for the large deep petrosal nerve) through communication with the carotid plexus
This nerve may be involved by paraganglioma, in this location referred to as glomus jugulare or glomus tympanicum tumours.