Glossopharyngeal Nerve(redirected from ninth cranial nerve)
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Related to ninth cranial nerve: vagus
glossopharyngeal nerve[¦gläs·ō·fə′rin·jē·əl ‚nərv]
the ninth pair of cranial nerves. It consists of sensory, motor, and secretory fibers. The nuclei of the nerve are located in the medulla oblongata. The common trunk of the nerve emerges from the cranial cavity through the jugular foramen together with the vagus and accessory nerves and internal jugular vein.
The glossopharyngeal nerve supplies the mucous membrane of the radix linguae, pharynx, soft palate, eustachian tube, and tympanic cavity with sensory fibers. The taste fibers that innervate the posterior third of the tongue enter the peripheral portion of the taste receptors. The motor and secretory fibers innervate some pharyngeal muscles and the parotid gland, respectively. One of the sensory branches of the glossopharyngeal nerve also carries impulses from the carotid sinus, thereby participating in the regulation of blood circulation.
Injury to the glossopharyngeal nerve impairs swallowing and taste. In some cases, compression of the nerve causes neuralgia, manifested chiefly by pain in the regions innervated by it.