glossopharyngeal nerve(redirected from CN IX)
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Related to CN IX: Cranial nerves, CN V, CN XII
glossopharyngeal nerve(glô′sō-fə-rĭn′jē-əl, -jəl, -făr′ən-jē′əl, glŏs′ō-)
Taste fibers from the posterior third of the tongue join visceral sensory fibers from the pharynx, auditory tube, middle ear, carotid sinus, and carotid body and run back to their neuronal cell bodies in the superior and inferior ganglia of the glossopharyngeal nerve, located in the jugular foramen. The axons of these ganglionic neurons follow the glossopharyngeal roots into the hindbrain where they synapse in the nucleus of the tractus solitarius and the spinal nucleus of the trigeminal nerve.
The glossopharyngeal nerve emerges from the medulla as a line of small rootlets just anterior to the rootlets of the vagus nerve (CN X). The glossopharyngeal rootlets collect into a single nerve that emerges from the skull through the jugular foramen, along with the vagus and spinal accessory (CN XI) nerves. The glossopharyngeal nerve then divides into branches as it runs along the stylopharyngeus muscle.