![]() ![]() By way of the tympanic branch of the glossopharyngeal nerve ( Jacobson’s nerve), sensation is supplied to the tympanic membrane, eustachian tube, and the mastoid region. The sensory fibers carried in the glossopharyngeal nerve include taste afferents, supplying the posterior third of the tongue and the pharynx, and general visceral afferents from the posterior third of the tongue, tonsillary region, posterior palatal arch, soft palate, nasopharynx, and tragus of the ear. The motor fibers originate from the rostral nucleus ambiguus and innervate the stylopharyngeus muscle (a pharyngeal elevator) and (with the vagus nerve) the constrictor muscles of the pharynx. The nerve winds around the lower border of the stylopharyngeus muscle (which it supplies) and then penetrates the pharyngeal constrictor muscles to reach the base of the tongue. Within or distal to this foramen, the glossopharyngeal nerve widens at the superior and the petrous ganglia and then descends on the lateral side of the pharynx, passing between the internal carotid artery and the internal jugular vein. These three nerves then travel together through the jugular foramen. The nerve emerges from the posterior lateral sulcus of the medulla oblongata dorsal to the inferior olive in close relation with cranial nerve X (the vagus nerve) and the bulbar fibers of cranial nerve XI (the spinal accessory nerve) ( Fig. The glossopharyngeal nerve contains motor, sensory, and parasympathetic fibers. Cranial Nerves IX and X (The Glossopharyngeal and Vagus Nerves)Īnatomy of Cranial Nerve IX (Glossopharyngeal Nerve) ![]()
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