|Inferior ganglion of glossopharyngeal nerve|
|Latin||Ganglion inferius nervi glossopharyngei, ganglion petrosum|
|Anatomical terms of neuroanatomy|
The inferior ganglion of the glossopharyngeal nerve (petrous ganglion) is larger than the superior ganglion and is situated in a depression in the lower border of the petrous portion of the temporal bone which is named fossula petrosa.
It contains the bodies of general somatic sensory neurons (GSA fibers) and general visceral sensory neurons (GVA fibers) that innervate the pharynx, tonsils, tongue, middle ear, auditory tube and the ear canal. It also contains the neurons that innervate the carotid sinus baroreceptors (which is a type of mechanoreceptors) and carotid body (chemoreceptors) through the Hering's nerve and the rami glomi carotici respectively. Rr. glomi carotici are the branches of vagus nerve but the origin of these fibers is glossopharyngeal nerve.
This ganglion also plays a role in taste as it contains cell bodies of special visceral sensory (SVA fibers) which innervate the posterior third of the tongue as well as some areas of the pharnyx. These taste fibers are branches of cranial nerves IX and X.