Anatomy & Organs

Timpani cavity – structure, function & diseases

Drum cavity

The physician understands the tympanic cavity to be a cavity in the middle ear in which the auditory ossicles are accommodated. In addition to the hearing process, the tympanic cavity is involved in middle ear ventilation and pressure equalization. The tympanic effusion is the most well-known complaint associated with the tympanic cavity.

What is the drum cave?

The tympanic cavity is a part of the middle ear. It is a cavity system with six different walls. This cavity system is particularly relevant for ventilation, sound amplification and pressure equalization. The tympanic cavity begins immediately behind the eardrum and consists of the tympanic dome, the middle tympanic space and the tympanic basement. The middle space forms the largest part and is directly adjacent to the eardrum.

The so-called oval window connects the tympanic cavity with the cochlea of ​​the inner ear . The auditory ossicles are also housed in the structure of the tympanic cavity. The anvil and malleus sit in the dome of the structure where the malleus is attached to the eardrum and articulates with the anvil and stirrup. With a length of around twelve to 15 millimeters, the tympanic cavity is around three to seven millimeters wide. The internal volume is around one cubic centimeter.

Anatomy & Structure

The drum cave has a total of six walls. From the cavity system, there are primarily connections to the nasopharynx and the inner ear through various windows and openings. In the upper part of the tympanic cavity there is access to the cranial bone. The upper limit of the tympanic cavity is a thin plate of bone, which is also called the tympanic roof. The internal carotid artery runs in the front wall of the middle part of the tympanic cavity.

The eardrum muscle is also located in this area. The tuba auditiva, which connects the tympanic cavity with the nasopharynx, also opens into the same wall. The lateral wall of the tympanic cavity is formed by the eardrum itself. This is where a nerve branch crosses, which is also known as the tympanic cord. The curved middle wall of the tympanic cavity separates the cavity structure from the inner ear. The posterior wall forms the boundary to the mastoid process of the cranial bone cavities.

Four arteries supply the tympanic cavity and open into lymph and nerve structures. The majority of the tympanic cavity is lined with a thin mucous membrane. This mucosa consists of an isoprismatic epithelium with mucus-producing goblet cells. In the area of ​​the auditory ossicles, this layer merges into a thick squamous epithelium.

Function & Tasks

Since the tympanic cavity is a cavity system, this anatomical structure is permanently filled with air. The ventilation of the entire middle ear takes place via the air-filled cavity system. In addition, the tympanic cavity is used for the functional accommodation of the auditory ossicles malleus, anvil and stirrup. These bones are connected to each other and together amplify all acoustic signals.

This is what makes the auditory impression possible in the first place, as people are familiar with it. The membrane of the tympanic cavity is able to vibrate for the sake of the bones. For example, if the eardrum vibrates due to sound, this is transmitted to the attached malleus. The hammer transmits the vibrations to the anvil and stirrup. From these two auditory ossicles, the sound is conducted into the inner ear. This transmission takes place through the oval window in the tympanic cavity. The tympanic cavity is thus significantly involved in the hearing process. The cavity system is also an instance of pressure equalization through the inflowing tuba auditiva, which mainly takes place via the nose and throat area.

Pressure equalization is particularly relevant in situations under water or at higher altitudes. If large differences in height or pressure are overcome in a very short time, there is a pressure gradient between the external auditory canal and the tympanic cavity. The eardrum is then pressed into the cavity system. In such situations, pressure equalization via the auditory tube ensures the integrity of the eardrum, but fluid is also drained from the middle ear through the auditory tube.

Diseases

The so-called tympanic effusion is one of the most common diseases of the tympanic cavity. This phenomenon is usually the result of a cold with a respiratory infection , but allergies can also trigger a tympanic effusion. As a rule, a purulent middle ear infection occurs as part of a tympanic effusion . The tuba auditiva swells and hardly lets any more air into the tympanic cavity.

The ventilation of the middle ear is no longer possible. High pressure builds up in the tympanic cavity and fluid builds up. As a result, the eardrum bulges inwards. Hearing loss usually occurs as well. Effusions in the tympanic cavity can lead to a chronic middle ear infection. After an ear examination , the doctor usually treats a tympanic effusion with medication. A rarer, but all the more serious disease of the middle ear is chronic bone suppuration. In this disease, the middle ear is constantly under pressure due to a disruption in the air supply.

The eardrum pulls into the middle ear and the chain of auditory ossicles in the tympanic cavity is damaged. The skin of the external auditory canal comes into contact with the lining of the middle ear and the ossicles slowly degrade in the context of aggressive inflammation. Otosclerosis can also cause the auditory ossicles in the tympanic cavity to deteriorate and promote deafness. Sometimes, however, paralysis of the facial nerve becomes noticeable as middle ear problems, since the facial nerve opens into the tympanic cavity there.

 

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.