Laryngeal nerve

The glossopharyngeal nerve (n. glossopharyngeus) contains sensory, motor and secretory (parasympathetic) fibers. The sensory fibers end on the neurons of the nucleus of the solitary tract, the motor fibers come out of the nucleus ambiguus, and the autonomic fibers come out of the inferior salivatory nucleus. The glossopharyngeal nerve comes out of the medulla oblongata with 4-5 roots behind the olive, next to the roots of the vagus and accessory nerves. Together with these nerves, the glossopharyngeal nerve goes to the jugular foramen, to its anterior part. In the jugular foramen, the nerve thickens and forms the superior ganglion (ganglion superius), or intracranial ganglion. Under the jugular foramen, in the area of the petrosal fossa, is the inferior ganglion (ganglion inferius), or extracranial ganglion of the glossopharyngeal nerve. Both ganglia are formed by the bodies of pseudounipolar neurons. Their central processes are directed to the nucleus of the solitary tract. The peripheral processes of these cells follow from receptors located in the mucous membranes of the posterior third of the tongue, pharynx, tympanic cavity, from the carotid sinus and glomerulus.

After exiting the jugular foramen, the glossopharyngeal nerve passes onto the lateral surface of the internal carotid artery. Passing further between the internal carotid artery and the internal jugular vein, the glossopharyngeal nerve makes an arcuate bend with its convexity downwards, and is directed downwards and forwards between the styloglossus and styloglossus muscles to the root of the tongue. The terminal branches of the glossopharyngeal nerve are the lingual branches (rr. linguales), which branch out in the mucous membrane of the posterior third of the dorsum of the tongue. The branches of the glossopharyngeal nerve are the tympanic nerve, as well as the sinus, pharyngeal, styloglossus and other branches.

The tympanic nerve (n. tympanicus) contains sensory and secretory fibers (parasympathetic), departs from the inferior ganglion of the glossopharyngeal nerve into the petrosal fossa and into the tympanic canaliculus of the temporal bone. In the mucous membrane of the tympanic cavity, the nerve forms the tympanic plexus (plexus tympanicus) together with the siltatic postganglionic fibers of the carotid-tympanic nerves (nn. caroticotympanici). The sensory fibers of the tympanic plexus innervate the mucous membrane of the tympanic cavity, the cells of the mammillary process, and the auditory tube (tubal branch, r. tubarius). The fibers of the tympanic plexus gather into the lesser petrosal nerve, which exits the tympanic cavity onto the anterior surface of the pyramid of the temporal bone through the cleft of the canal of the lesser petrosal nerve. Then this nerve exits the cranial cavity through the cartilage of the lacerated foramen and enters the ear (parasympathetic) ganglion. The small petrosal nerve (n. petrosus minor) is formed by preganglionic parasympathetic secretory fibers for the parotid gland, which are axons of the inferior salivary nucleus.

The sinus branch (r. sinus carotici), or Hering's nerve, is sensory and goes down to the bifurcation area of the common carotid artery and to the carotid glomerulus located here.

The pharyngeal branches (rr. pharyngei, s. pharyngeales) in the amount of two or three enter the wall of the pharynx from the lateral side. Together with the branches of the vagus nerve and the sympathetic trunk, they form the pharyngeal plexus.

The branch of the stylopharyngeal muscle (r. musculi stylopharyngei) is motor and goes forward to the muscle of the same name.

The tonsillar branches (rr. tonsillares) are sensitive, depart from the glossopharyngeal nerve before it enters the root of the tongue, and are directed to the mucous membrane of the palatine arches and to the palatine tonsil.

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