What Is the Glossopharyngeal Nerve?

The ninth pair of cranial nerves is called the glossopharyngeal nerve, which is responsible for the sensation of the mucous membrane of the throat, part of the salivary glands and the taste of the back third of the tongue, and the tenth pair of vagus nerves is responsible for the movement of the throat muscles. It mainly controls the styloid pharyngeal muscle, parotid gland, part of the taste buds and collects the sensations from the back of the ear.

The ninth pair of cranial nerves is called the glossopharyngeal nerve, which is responsible for the sensation of the mucous membrane of the throat, part of the salivary glands and the taste of the back third of the tongue, and the tenth pair of vagus nerves is responsible for the movement of the throat muscles. It mainly controls the styloid pharyngeal muscle, parotid gland, part of the taste buds and collects the sensations from the back of the ear.

Chinese name

Glossopharyngeal nerve

Foreign name

Glossopharyngeal nerve

Visiting department

Internal medicine

Common disease

Posterior pharyngeal wall, tonsils, tongue base, etc.

Overview of the glossopharyngeal nerve

The root filaments of the glossopharyngeal nerve emerge from the front of the posterior sulcus of the medulla oblongata and exit the jugular foramen with the vagus and accessory nerves. There is an enlarged upper ganglia on the neural stem in the hole, and a slightly larger lower ganglia is formed when the hole is exited. After the glossopharyngeal nerve emerges from the skull, it first moves in the neck and between the veins, then bows forward, and reaches the root of the tongue through the medial side of the hyoid muscle. Its branches are as follows:

Tympanic nerve

The tympanic nerve originates from the inferior ganglia and enters the tympanic cavity. It forms a tympanic plexus with the sympathetic nerve fibers in the mucosa of the lateral wall of the tympanic cavity, and emits many small branches, which are distributed to the mucosa of the tympanic cavity, mastoid ovary and eustachian tube. The terminal branch of the tympanic nerve is a small petrosal nerve, which contains parasympathetic fibers. It exits the tympanic ear ganglion. After exchanging neurons, it is distributed to the parotid gland via the temporal auricular nerve to control its secretion.

Carotid sinus branch

Carotid sinus branches 1 to 2 are issued below the jugular foramen, descend along the internal carotid artery, and are distributed in the carotid sinus and the carotid artery. The carotid sinus is a baroreceptor, and the carotid bulb is a chemoreceptor, which senses changes in blood pressure and carbon dioxide concentration in the blood, and reflexively adjusts blood pressure and breathing.

Tongue branch

The tongue branch is the terminal branch of the glossopharyngeal nerve. It is deep through the hyoid hyoid muscle and is distributed in the mucous membranes and taste buds of the third of the back of the tongue. The general sensation and taste of the mucosa.

Styloid pharyngeal muscle branch

It is separated by the glossopharyngeal nerve and innervates the styloid pharyngeal muscle.

Tonsil branch

The mucous membranes of the palatine tonsils, pharyngeal arch, and lingual arch are generally visceral.

Pharynx

Pharyngeal plexus is formed on the pharyngeal wall with the pharyngeal branch of the vagus nerve and sympathetic nerves. The pharyngeal branch of the glossopharyngeal nerve is usually viscerally. After the glossopharyngeal nerve is injured, the pharyngeal and posterior 1/3 of the tongue are impaired, the pharyngeal reflex disappears, and the taste of the posterior 1/3 of the tongue is lost.

Glossopharyngeal nerve fiber composition

Contains five fiber ingredients:

1. Special visceral motor fibers: originate from the suspected nucleus and dominate the styloid muscle.

2. Parasympathetic fibers: distributed in the parotid glands after exchanging neurons in the ear ganglia, secreted by the glands.

3. General visceral sensory fibers: The cell body is also located in the inferior ganglia, and the central process is finally a solitary nucleus. The surrounding processes are distributed in the mucosa of the pharynx, posterior 1/3 of the tongue, eustachian tube, and tympanic cavity, and the carotid sinus and carotid arteries are small. ball.

4. Special visceral sensory fibers: the soma is located in the inferior ganglia at the jugular foramen, the central process is finally the solitary nucleus of the brain stem, and the peripheral processes are distributed in the taste buds behind the tongue 1/3.

5. Somatosensory fibers: Cell bodies are located in the upper ganglia and are distributed behind the ear skin.

Glossopharyngeal nerve

Glossopharyngeal neuralgia is a paroxysmal pain in the base of the tongue and tonsils on one side of the pharynx. The incidence is very low, only about one in two million. Sudden onset of pain can radiate to the ipsilateral tongue and deep ear for several seconds to several tens of seconds, accompanied by increased saliva secretion, which can be induced by speaking, swallowing, touching the affected pharyngeal wall and mandibular angle. Knife-cut or burning-like pain. The disease itself is not fatal or disabling, but it is rarely possible to heal itself.

Clinical Anatomy of Glossopharyngeal Nerve in the Skull Base Area of Glossopharyngeal Nerve

The extracranial part of the glossopharyngeal nerve travels out of the cranial cavity through the jugular foramen along with the branch glossopharyngeal nerve, the vagus nerve, and the accessory nerve. At the jugular foramen, the glossopharyngeal nerve is located on the anterior and lateral side of the foramen, and the vagus nerve and the accessory nerves are located at the posterior and outer parts of the foramen. They are separated by a dura mater. The glossopharyngeal nerve, vagus nerve, accessory nerves and inferior petrosal sinuses, internal jugular vein exit the cranial orifice through the jugular foramen. GphN swells near the lower edge of the jugular foramen to form a lower ganglion (also known as a rock ganglion). The shape slightly above the lower ganglion is smaller than the upper ganglion of the lower ganglion. The inferior ganglia is located in the rock fossa below the foramen of the jugular vein. It is tightly bound to surrounding tissues and difficult to separate.

The branches and communication branches issued from this ganglion are: The tympanic nerve enters the tympanic canal from the initiation of the inferior ganglion, enters the tympanic canal through the tympanic canal, and the origin is mostly on the posterolateral side of the ganglia; send out small branches to connect with the ear branch of the vagus nerve; sometimes send out 1 or 2 communication branches to the lower end of the upper ganglion of the vagus nerve. On the slightly inferior side of the hypopharyngeal nerve ganglion, thin branches are issued by the neural trunk, walking inward and downward, together with the branches of the vagus nerve and the branches of the superior cervical ganglion to form the pharyngeal plexus. The pharyngeal plexus is located at the level of the large angle of the hyoid bone in the middle pharynx. After the glossopharyngeal nerve emerges from the jugular foramen, it is located on the anterolateral side of the vagus and accessory nerves, the anterior medial side of the internal jugular vein, and passes downwards between the internal carotid artery and the internal jugular vein. Downward oblique, the carotid sinus branch is issued before leaving the carotid sheath. The trunk is located on the deep side of the styloid process and styloid muscles, first on the lower edge of the styloid process, then on the outer side, and in the middle of the styloid process. The lower edge bends forward and sends out branches to innervate the muscle, and the main trunk is on the inside of the hyoid hyoid muscle, crossing the pharyngeal constrictor and styloid hyoid bone ligament forward, emitting its terminal branches (tongue branch and tonsil branch). . On the deep side of the styloid process and its attached muscles, there is a large ascending pharyngeal artery originating from the external carotid artery, which crosses the glossopharyngeal nerve trunk. The distance of the glossopharyngeal nerve from the deep side of the styloid pharyngeal muscle to the carotid bifurcation is 23 to 47 mm, and the distance to the mastoid tip is 7 to 15 mm. The distance from the midpoint of the mastoid tip to the angle of the mandible to the jugular foramen is (21.32 ± 2.03) mm on the left and (21.42 ± 2.05) mm on the right. It was found that the glossopharyngeal nerve was the smallest diameter nerve in the cranial nerve in the posterior group, and its maximum diameter was measured to be about 1.2 mm.