The tympanic nerve is a part of the IX cranial nerve. It is located in the middle ear. There, it innervates the eustachian tube.
What is the tympanic nerve?
The tympanic nerve is a branch of the glossopharyngeal nerve. This is the IXth cranial nerve. Its main function is to regulate the muscles of the pharynx. This is directly related to the ear. The tympanic nerve is called the tympanic cavity nerve. It is generally somato-sensitive to the middle ear as well as the tuba auditiva. The tympanic nerve consists of parasympathetic fibers. These have the task of innervating bodily functions. Through their activity, the organism regenerates itself. In addition, its energy reserves are built up. This function helps the organism to be in a state of internal balance. The state of homeostasis is sought by every organ as well as all functions of the body. The tympanic nerve also has a visceromotor effect on the parotid gland. This provides about 25% of the total saliva production. The parotid gland supplies the posterior third of the tongue. Its activity is of great importance in the swallowing process. In addition, it also plays an essential role in speech formation.
Anatomy and structure
The IX cranial nerve has much in common with the X. Cranial Nerve in common. Like the vagus nerve, the glossopharyngeal nerve innervates parts of the tongue and pharynx. The glossopharyngeal nerve emerges from the brainstem and travels downward to the root of the tongue. Immediately below the jugular foramen, the tympanic nerve exits. It consists of somatosensory and parasympathetic fibers. Beginning at the inferior ganglion, its path continues through the tympanic canal of the petrous bone to the tympanic cavity. This is located in the middle ear. The tympanic nerve ends there at the same time. It takes up additional sympathetic fibers from the carotid plexus at this point of the organism. With them, it forms the tympanic plexus. Thus, it sensitively supplies the middle ear and the auditory tube. Together with the petrosal minor nerve, the tympanic nerve forms the Jacobson’s anastomosis.
Function and Tasks
The IX cranial nerve has an exceptionally important role in the swallowing process. In particular, the glossopharyngeal nerve assumes an important function in the connection from the oral to the nasal cavity. In addition, it has an essential role in speech formation. It prevents nasal pronunciation. As part of the glossopharyngeal nerve, the tympanic nerve innervates the parotid gland. This is called the parotid gland and produces ¼ of all saliva in the mouth. The entire posterior third of the tongue is thus adequately supplied. This is where a significant part of taste perception takes place. Above all, the quality of the taste sensation “bitter” takes place at this point. It also supplies the middle ear and the tuba auditiva. This sits directly behind the eardrum. The eardrum is a membrane that curves inward or outward. It responds to positive or negative pressure and is called the membrana tympani. The flexible membrane separates the outer ear from the middle ear. With a length of 35 mm, the tuba auditiva is very small. One of its functions is to ventilate the middle ear. This is necessary to create a pressure balance between the middle ear and the outer atmosphere. This is the only way to ensure optimal sound wave transmission from the outer ear to the inner ear. The functioning of the uvula is influenced by the interaction of the tympanic nerve with the other glands of the middle ear. This has an important function in swallowing. The absorption of liquids is correctly directed through the palatine area into the esophagus. This is to prevent fluids from entering the nasal area.
Diseases
Impaired functioning of the tympanic nerve affects the functioning of the auditory tube as well as the parotid gland. During a cold, swelling of the mucosa occurs. This presses on the tympanic nerve and deprives it of necessary space in the middle ear. As a result, sound transmission is impaired. Within a very short time, the pressure balance from the tympanic cavity is minimized. This reduces the ability of the tympanic membrane to vibrate. This leads to a reduction in hearing ability. As soon as the functional capacity of the tympanic nerve is reduced, there is interference with the cleaning in the tympanic cavity.The consequence is that bacteria can spread in the tympanic cavity. This means that the drainage of secretions from the tympanic cavity is no longer guaranteed. This increases the likelihood of a purulent middle ear infection. As soon as the functioning of the parotid gland is impaired, there is a reduction in saliva production. This affects speech formation as well as the swallowing process. The activity of the uvula is affected. This can result in inadequate separation of the oropharynx from the nasopharynx in the area of the soft palate during swallowing as well as during speech. This is the area where the union of the oral and pharyngeal cavities occurs. As a result, fluids leak back out of the nose when swallowing. This can happen especially when drinking, but also when ingesting thin-bodied food. When speaking, a nasally pronunciation occurs. In extreme cases, the gag reflex may fail. If a tumor forms in the area of the middle ear, the functionality of the tympanic nerve is also restricted. In individual cases, nerve pain may occur. These are neuralgias of the tympanic nerve. Patients report a sudden pain associated with pain in the ear and throat.
