Along the superior aspect of the tympanic cavity, the tympanic plexus converges to form the lesser petrosal nerve which provides preganglionic parasympathetic innervation to the otic ganglion. The tympanic nerve (nerve of Jacobson) arises from the inferior ganglion, traverses the tympanic canaliculus and provides innervation to the middle ear cavity, mastoid air cells and auditory tube via the tympanic plexus. Axons reaching the rostral SN convey gustatory sense from the posterior one-third of the tongue those reaching more caudal SN relay visceral sensory information from the pharynx, middle ear, oral cavity and carotid sinus/body. Axons reaching the STN convey pain and thermal sense from the external ear. ![]() These primary sensory neurons project to the spinal trigeminal nucleus (STN) or solitary nuclei (SN). Together, these sensory ganglia include pseudounipolar cell bodies that provide general somatic, visceral and special visceral innervation across the territory of CN IX. There are two sensory ganglia associated with CN IX: the superior and inferior (petrosal). The ISN provides preganglionic parasympathetic innervation to scattered ganglion cells in the tympanic cavity and otic ganglion. The NA includes lower motor neurons that provide innervation to the stylopharyngeus muscle. ![]() Efferent axons in CN IX are derived from the nucleus ambiguous (NA) and the inferior salivatory nucleus (ISN).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |