OTIC GANGLION
INTRODUCTION :
It is a peripheral parasympathetic ganglion which relays
secretomoter fibres to the parotid gland.
Topographically , it is intimately related to the mandibular
nerve , but functionally it is a part of the glossopharyngeal nerve.
SIZE AND SITUATION
a)
It is 2-3 mm in size , and is situated in the
infratemporal fossa ,just below the foramen ovale.
b)
It lies medial to the mandibular nerve , and
lateral to the tensor veli palatine.
c)
It surrounds the origin of the nerve to the
medial pterygoid.
CONNECTIONS AND BRANCHES
a)
The motor or parasympathetic root is formed by
the lesser petrosal nerve.
b)
The preganglionic fibres are derived from the
inferior salivary nucleus-the ninth nerve, its tympanic branch, the tympanic
plexus –the lesser petrosal nerve to reach the ganglion.
c)
The postganglionic or secretomotor fibres pass
through the auriculotemporal nerve.they are vasomotor in function .
d)
The sensory root comes from the
aurioculotemporal nerve and is sensory to the parotid gland.
Other fibres passing through the ganglion are as follows.
a)
The nerve to the medial pterygoid gives a motor
root to the ganglion which passes through it without relay and supplies
medially placed tensorveli palatini and laterally placed tensor tympani
muscles.
b)
The chorda tympani nerve is connected to the
otic ganglion and also to the nerve of the pterygoid canal. These connectins
provide an alternative pathway of taste from the anterior two-thirds of the
tongue. These fibres do not pass through the middle ear.
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