The tonsillar branches of the glossopharyngeal nerve are also 2 - 3 side branches carrying sensory fibers. This plexus eventually innervates the mucosa lining the upper part of the pharynx. Together with branches of the vagus nerve (CN X) and laryngopharyngeal nerve of the cervical sympathetic trunk, these branches participate in forming the pharyngeal nerve plexus on the posterior wall of the pharynx. The pharyngeal branches of the glossopharyngeal nerve are 2 to 3 side branches of the CN IX that mainly carry sensory fibers. The branch to the stylopharyngeus muscle is a small motor branch of the glossopharyngeal nerve supplying the stylopharyngeus muscle. Tympanic nerve (sensory and parasympathetic).Branch to the stylopharyngeus muscle (motor).On its course, the glossopharyngeal nerve gives off several side branches, including the following: The lingual branches of the glossopharyngeal nerve innervate the mucosa of the posterior one-third of the tongue between the terminal sulcus and the epiglottis with general visceral afferent fibers, vallate papillae with special visceral afferent (taste) fibers, and lingual glands with general visceral efferent (parasympathetic) fibers. Then it wraps around the stylopharyngeus muscle and passes between the superior and middle pharyngeal constrictor muscles, enters the oral part of the pharynx, reaching the root of the tongue, where it diverges into lingual branches. Both ganglia contain cell bodies of sensory neurons - pseudounipolar neurons - with dendrites receiving information in the periphery and traveling to the central nervous system (CNS) via the glossopharyngeal nerve and axons traveling to the sensory nuclei in the brainstem.Īfter emerging on the external surface of the skull, the glossopharyngeal nerve descends along with the stylopharyngeus muscle, at first, behind the internal carotid artery, and then between the same artery and the internal jugular vein. The CN IX forms two enlargements in the area of the jugular foramen: the superior ganglion in the jugular foramen and the inferior ganglion of the glossopharyngeal nerve below the jugular foramen at the level of petrosal fossula. The glossopharyngeal nerve, along with the two other mentioned cranial nerves, goes forward and laterally and leaves the skull through the jugular foramen. The ninth cranial nerve emerges from the medulla oblongata on the posterolateral sulcus together with the vagus nerve (CN X) and accessory nerve (CN XI). Glossopharyngeal nerve course and branches Inferior salivatory nucleus (parasympathetic) - supplies the parotid gland.Solitary tract nucleus (sensory) - shared with the vagus (CN X) and intermediate portion of the facial nerve (CN VII) receives fibers from the posterior one-third of the tongue.Nucleus ambiguous (motor) - shared with the vagus (CN X) and accessory nerve (CN XI) provides innervation for the stylopharyngeus and the superior pharyngeal constrictor muscles.The glossopharyngeal nerve has three nuclei located in the lower aspect of the rhomboid fossa:
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