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 in the infratemporal fossa and on the medial surface of the mandibular nerve. It is functionally associated with the glossopharyngeal nerve and 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).

This ganglion is occasionally absent.

Structure

It is in relation, laterally, with the trunk of the mandibular nerve at the point where motor and sensory roots join; medially, with the cartilaginous part of the auditory tube , and the origin of the tensor veli palatini; posteriorly, with the middle meningeal artery

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.

The preganglionic parasympathetic fibers originate in the inferior salivatory nucleus of the glossopharyngeal nerve. They leave the glossopharngeal nerve by its tympanic branch and then pass via the tympanic plexus and the lesser petrosal nerve to the otic ganglion. Here, the fibers synapse, and the postganglionic fibers leave the ganglion nad join the auriculotemporal nerve. They are conveyed by this nerve to the parotid gland and serve as secretomotor fibers. It also probably recieves a motor root from the facial nerve via this route.

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

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

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)