Otic ganglion

The otic ganglion is situated adjacent to the main trunk of mandibular (V3) nerve inside the infratemporal fossa, as it exits the foramen ovale. It is formed by cell bodies of post-ganglionic parasympathetic neurons.

The otic ganglion is anatomically linked with the auriculotemporal nerve, which supplies the parotid gland. It also gives motor branches to innervate muscles such as tensor tympani and tensor veli palatini. Even though the ganglion is topographically connected to the mandibular nerve, it also possesses a strong functional connection with the glossopharyngeal nerve.

The otic ganglion receives four important roots to it, namely the sensory, motor, parasympathetic and sympathetic roots:

The sensory root comprises of afferent fibers which transmit general sensations from the parotid capsule, auricle, external acoustic meatus, tympanic membrane and temporomandibular joint. These neurons course through the auriculotemporal nerve > then pass unrelayed through the ganglion > and end up synapsing in the sensory trigeminal ganglion.

The motor root is formed by the efferent neurons that arrive from the medial pterygoid nerve. They pass unrelayed through the ganglion and end up innervating tensor tympani and tensor veli palatini muscles.

Parasympathetic root is secretomotor and comprises of preganglionic parasympathetic neurons which arise from the inferior salivatory nucleus in the brainstem and come into the otic ganglion via the lesser petrosal nerve (from tympanic plexus). After synapsing inside the ganglion, the post-ganglionic parasympathetic neurons channelize through the auriculotemporal nerve to innervate the parotid gland.

Sympathetic root comprises of post-ganglionic sympathetic neurons which come off from the neuronal plexus around the middle meningeal artery.