Otic ganglion

Otic ganglion
The otic ganglion and its branches.
Mandibular division of trigeminal nerve, seen from the middle line. The small figure is an enlarged view of the otic ganglion.
Details
From	lesser petrosal nerve
Innervates	parotid gland
Identifiers
Latin	ganglion oticum
TA98	A14.3.02.014
TA2	6671
FMA	6967
Anatomical terms of neuroanatomy

The otic ganglion is a small, oval shaped, flattened parasympathetic ganglion of a reddish-gray color, located immediately below the foramen ovale; it lies on the medial surface of the mandibular nerve in the infratemporal fossa. It innervates the parotid gland for salivation.

It is one of four parasympathetic ganglia of the head and neck. (The others are the submandibular ganglion, pterygopalatine ganglion, and ciliary ganglion).

It is occasionally absent.

Structure

Branches of communication

Its sympathetic postganglionic fibers consists of a filament from the plexus surrounding the middle meningeal artery.

Preganglionic parasympathetic fibers originate from the glossopharyngeal nerve via the lesser petrosal nerve. The lesser petrosal nerve is a continuation of the glossopharyngeal nerve after it exits the skull via the jugular foramen and innervates the tympanic plexus. Postganglionic parasympathetic fibers travel with the sympathetic fibers of the auriculotemporal nerve (a branch of CN V3) to supply the parotid gland. All postsynaptic parasympathetics will use some branch of the Trigeminal Nerve to get from one of four parasympatheic ganglia (Otic, Ciliary, Submandibular, and Pterygopalatine) to their destinations in either smooth muscle or glandular tissue (secretomotor).

A slender filament (sphenoidal) ascends to the nerve of the Pterygoid canal, and a small branch connects with the chorda tympani.

It is connected by two or three short filaments with the nerve to the Pterygoideus internus, from which it may obtain a motor, and possibly a sensory root.

Distribution

Its branches of distribution are: a filament (V3 to Medial Pterygoid mm) to the Tensor tympani, and one to the Tensor veli palatini.

The former passes backward, lateral to the auditory tube; the latter arises from the ganglion, near the origin of the nerve to the Pterygoideus internus, and is directed forward.

The fibers of these nerves are, however, mainly derived from the nerve to the Pterygoideus internus.

Clinical significance

Frey's syndrome in which salivation will induce perspiration at the parotid region, accompanied by erythema.

Additional images

• 
  Plan of the facial and intermediate nerves and their communication with other nerves.
• 
  Diagram of efferent sympathetic nervous system.

References

This article incorporates text in the public domain from page 897 of the 20th edition of Gray's Anatomy (1918)

• Shimizu T (1994). "Distribution and pathway of the cerebrovascular nerve fibers from the otic ganglion in the rat: anterograde tracing study". J. Auton. Nerv. Syst. 49 (1): 47–54. doi:10.1016/0165-1838(94)90019-1. PMID 7525688.

External links

• cranialnerves at The Anatomy Lesson by Wesley Norman (Georgetown University) (V, IX)