Tympanic nerve

Branch of the glossopharyngeal nerve

The tympanic nerve is a branch of the glossopharyngeal nerve (cranial nerve IX) that plays a crucial role in the innervation of the middle ear. It is involved in the sensory supply to the tympanic cavity and contributes to the formation of the tympanic plexus.

Anatomy

The tympanic nerve arises from the glossopharyngeal nerve shortly after it exits the jugular foramen. It enters the middle ear through the tympanic canaliculus, a small canal in the petrous part of the temporal bone.

Tympanic Plexus

Within the middle ear, the tympanic nerve forms the tympanic plexus on the promontory of the cochlea. This plexus provides sensory innervation to the mucous membrane of the tympanic cavity, the mastoid air cells, and the auditory tube.

Lesser Petrosal Nerve

Fibers from the tympanic plexus converge to form the lesser petrosal nerve, which carries preganglionic parasympathetic fibers to the otic ganglion. These fibers are involved in the innervation of the parotid gland.

Function

The primary function of the tympanic nerve is to supply sensory innervation to the mucosa of the middle ear. It also plays a role in the parasympathetic innervation of the parotid gland via the lesser petrosal nerve.

Clinical Significance

Damage to the tympanic nerve can result in loss of sensation in the middle ear and may affect the function of the parotid gland. Conditions such as glossopharyngeal neuralgia can involve the tympanic nerve, leading to pain in the ear and throat.

Images

Diagram of the tympanic nerve and its connections.

The course and connections of the glossopharyngeal nerve.

The tympanic plexus and its branches.

The otic ganglion and its connections.

Related Pages

• Glossopharyngeal nerve
• Middle ear
• Otic ganglion
• Parotid gland

References

• Standring, S. (2020). Gray's Anatomy: The Anatomical Basis of Clinical Practice. 42nd Edition. Elsevier.
• Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2018). Clinically Oriented Anatomy. 8th Edition. Wolters Kluwer.