Thursday, February 3, 2011

Glossopharyngeal Nerve (CN IX)

The Glossopharyngeal nerve is the ninth cranial nerve (CN IX). It consists of both motor and sensory fibers and emerges from the brain stem as the most rostral of a series of nerve rootlets that protrude between the olive and inferior cerebellar peduncle. The CN IX supplies the tongue, throat, and one of the salivary glands (the parotid gland). Problems with the glossopharyngeal nerve result in trouble taste and swallowing. Compared with other lower cranial nerves, the glossopharyngeal nerve (GPhN) is well hidden within the jugular foramen, at the infratemporal fossa, and in the deep layers of the neck. "Glosso-" comes from the Greek "glossa", the tongue and "pharynx" is the Greek for throat. So the glossopharyngeal nerve is the nerve that serves the tongue and throat.

Glossopharyngeal Nerve Overview.
The glossopharyngeal nerve consists of five components with distinct functions: Brancial motor (special visceral efferent) - supplies the stylopharyngeus muscle. Visceral motor (general visceral efferent) provides parasympathetic innervation of the smooth muscle and glands of the pharynx, larynx, and viscera of the thorax and abdomen. Visceral sensory (general visceral afferent) carries visceral sensory information from the carotid sinus and body. General sensory (general somatic afferent) provides general sensory information from the skin of the external ear, internal surface of the tympanic membrane, upper pharynx, and the posterior one-third of the tongue. Special sensory (special afferent) provides taste sensation from the posterior one-third of the tongue.

Glossopharyngeal Nerve (Video)