Glossopharyngeal nerve

Course of the glossopharyngeal nerve in relation to the accessory nerve and vagus nerve

The paired glossopharyngeal nerve (from ancient Greek γλῶσσα glōssa 'tongue' and φάρυγξ phárynx 'throat', also known as the ninth cranial nerve , N. IX ), belongs to the so-called vagus group and is the third branchial arch nerve in terms of evolution . The glossopharyngeal nerve innervates the tongue and throat . It has sensitive, sensory ( taste perception ), motor and parasympathetic components.

origin

The core areas of its parasympathetic ( nucleus salivatorius inferior ) and motor ( nucleus ambiguus ) nerve fibers lie in the medulla oblongata . The nerve leaves the cranial cavity through the throttle hole ( jugular foramen ), where it receives sensory / sensory fibers from two ganglia . In mostly located still within the cranial cavity superior ganglion (with animals: Ganglion proximal ) are the nerve cell bodies of the afferent fibers for touch, pain and temperature stimuli in companies located outside the cranial cavity inferior ganglion (also petrosal ganglion , with animals: Ganglion distal ) the of the taste fibers. Both correspond to the spinal ganglion of a spinal nerve .

Branches of the glossopharyngeal nerve

Tympanic nerve

The tympanic nerve ("tympanic cavity nerve ") originates from the inferior ganglion and supplies the middle ear sensitively. In the middle ear it forms the tympanic plexus , from which the minor petrosus nerve arises, which leads parasympathetic fibers to the otic ganglion (so-called Jacobson's anastomosis ). There the fibers are switched to the second neurons and reach the parotid gland via the auriculotemporal nerve and the buccal nerve to the cheek glands, the secretion of which is stimulated.

Ramus pharyngeus

The ramus pharyngeus (" pharyngeal branch") forms the pharyngeal plexus with pharyngeal branches of the vagus nerve and sympathetic fibers from the superior cervical ganglion . This plexus of nerves supplies the striated muscles of the pharynx with motor and the pharyngeal mucosa sensitively. It is therefore also responsible for the gag reflex and the swallow reflex .

Rami linguales

The rami linguales (" tongue branches") convey touch, temperature, pain and taste sensations from the back third of the tongue .

More branches

The ramus sinus carotici runs to the sinus caroticus and the carotid body . Both are sensors of the circulatory and respiratory centers in the medulla oblongata .

The tonsil rami innervate the tonsils and the mucous membrane of the throat.

The ramus musculi stylopharyngei caudalis innervates the muscle of the same name, a pharyngeal head.

Diseases

Classification according to ICD-10
G52.1	Diseases of the glossopharyngeal nerve (IX cranial nerve)
ICD-10 online (WHO version 2019)

Glossopharyngeal spasm

The Glossopharyngeuskrampf, also known as throat spasm , Pharyngismus or glossopharyngeal spasm called (English), is caused by a spasm triggered by the glossopharyngeal innervated muscles. It occurs mainly in tetanus , rabies and irritation from foreign bodies (see also dysphagia ).

Glossopharyngeal palsy

Damage to the glossopharyngeal nerve leads to paralysis of the pharyngeal head muscles and thus to swallowing disorders ( dysphagia ). They are often associated with damage to the vagus nerve. Paralysis of the two cranial nerves occurs z. B. in central nervous diseases such as distemper and rabies and are the reason why the patients (animals, with rabies also humans) are not able to drink themselves. Even toxins of Clostridium ( Tetanus , botulism ) can disorders of nerve-muscle coupling and u. a. also lead to disorders of the two cranial nerves and the act of swallowing.

Glossopharyngeal neuralgia

This is a rare pain picture as a form of neuralgia , which is caused by partially attack-like pain in the area of the hypopharynx , the base of the tongue , the tonsils and the ear region . B. by chewing, swallowing, speaking or applying pressure can come about. If the carotid ramus is involved, reflex bradycardia or asystole can also occur. The cause is usually local demyelinating of the nerve branches due to pulsation of a neighboring vessel. This can lead to the transmission of electrical impulses from epicritical nerve fibers (convey information about pressure, touch, vibration and conscious deep sensitivity) to protopathic nerve fibers (convey information about pain and temperature).

The disease is also called Collet-Sicard syndrome after its description .

literature

Martin Trepel: Neuroanatomy. Structure and function. 3rd, revised edition. Urban & Fischer, Munich a. a. 2004, ISBN 3-437-41297-3 .
Franz-Viktor Salomon: nervous system, systema nervosum . In: Franz-Viktor Salomon, Hans Geyer, Uwe Gille (Ed.): Anatomy for veterinary medicine. Enke, Stuttgart 2005, ISBN 3-8304-1007-7 , pp. 464-577.