What is Tympanic Membrane?
Define Tympanic Membrane - It is an ear membrane that vibrates in the reaction of the sound waves. In some of the higher vertebrates and humans formation of tympanic membranes is seen. It is present in between the outer and middle ear. The tympanic membrane is also called the eardrum or myringa. We can know the different parts of it by referring to the below tympanic membrane diagram. Here, we will learn about the tympanic membrane anatomy.
[Image: Tympanic membrane diagram]
The main function of the tympanic membrane is to transmit sound from the air to the ossicles inside the middle ear and also to the oval window in the fluid-filled cochlea. People with ruptured tympanic membranes have extreme difficulty in hearing and possibly it might even result in the complete loss of hearing.
Tympanic Membrane or Eardrum Structure
The tympanic membrane structure is oriented obliquely in the anteroposterior, mediolateral, and superoinferior planes, consequently, its super posterior end lies lateral to its anterior inferior end. The structure of the tympanic membrane relates to the middle cranial fossa and posteriorly to the ossicles and facial nerve, inferiorly to the parotid gland and anteriorly to its anteroinferior
Parts of Tympanic Membrane
The tympanic membrane is divided into two membranes: pars flaccida and pars tensa. Pars flaccida lies above the lateral process of the malleus between the notch of rivinus and the anterior and posterior malleal folds and it consists of the two layers which appear slightly pinkish in hue. And the pars tensa consists of the three main layers: skin, fibrous tissue, and mucosa. The periphery of the pars tensa forms the fibrocartilaginous ring called Gerlach's ligament. The middle fibrous layer consists of radial, circular and parabolic fibers and which encloses the handle of the malleus. Pars tensa is comparatively more robust and commonly associated with perforation.
Layers of Tympanic Membrane
The tympanic membrane mainly consists of three layers: the outer layer, the middle layer, and the inner layer. The outer layer is continuous along with the skin on the external canal and the inner layer is continuous with the mucous membrane lining the middle ear. The middle layer is between the two, a layer of radicle and circular fiber which gives the fiber its tension and stiffness. The tympanic membrane is well supplied with the blood due to blood vessels and it is extremely sensitive to pain because of its sensory nerve fibers.
Tympanic Membrane or Eardrum Anatomy
According to the tympanic membrane anatomy, it is the stiff, translucent, and diaphragm-like structure. It moves synchronously in response to the variations in air pressure, which constitute the sound waves. This drum vibrates through the ossicular chain to the cochlea, where the mechanical energy changes to electrochemical energy and streams through the eighth cranial nerves in the brain. The tympanic membrane with the ossicles acts as a transducer, which changes one form of energy to the other form.
Did You Know?
How thick is the tympanic membrane? The tympanic membrane is the thin and circular layer of the tissue, which makes the point between the external ear and the internal ear. The tympanic membrane is approximately 0.1mm thick and eight to ten millimeters in diameter and the mass weight is around 14mg.
FAQs on Tympanic Membrane
1. What exactly is the tympanic membrane?
The tympanic membrane, more commonly known as the eardrum, is a thin, semi-transparent, cone-shaped membrane. It acts as a partition, separating the external ear from the middle ear. Its main purpose is to receive sound vibrations from the air and transmit them to the tiny bones in the middle ear.
2. Where is the tympanic membrane located and what does it look like?
The tympanic membrane is situated at the end of the ear canal. A healthy eardrum has a pearly-grey and translucent appearance. It isn't flat; it's shaped like a cone that points inward toward the middle ear. This specific shape is crucial for effectively gathering and concentrating sound waves.
3. How does the eardrum actually help us hear sounds?
When sound waves enter the ear canal, they hit the tympanic membrane and cause it to vibrate. These vibrations are then transferred to the first of three tiny bones in the middle ear, the malleus (or hammer), which is directly attached to the eardrum. This action is the first step in converting airborne sound into mechanical signals that the brain can understand.
4. What are the main layers that make up the tympanic membrane?
The tympanic membrane is composed of three distinct layers, each with a specific function:
- The Outer Layer: This is a thin layer of skin that is continuous with the lining of the ear canal.
- The Middle Layer: This is a fibrous layer that provides the eardrum with its strength and flexibility.
- The Inner Layer: This is a mucous membrane that lines the middle ear cavity, keeping it moist.
5. What happens if the tympanic membrane is damaged or ruptured?
A ruptured tympanic membrane means there is a hole or tear in the eardrum, often caused by infection, loud noise, or injury. This can lead to symptoms like sudden ear pain, hearing loss, fluid drainage from the ear, and a ringing sound known as tinnitus. A rupture also breaks the protective barrier, making the middle ear more susceptible to infection.
6. Can a ruptured eardrum heal by itself?
Yes, in many instances, a small rupture in the tympanic membrane can heal naturally within a few weeks. The body's own repair mechanisms can close the tear. However, for larger perforations or those that don't heal properly, a doctor may need to intervene with a patch or a surgical procedure to fix the hole and prevent complications.
7. Why is the tympanic membrane important for more than just hearing?
Beyond its primary role in hearing, the tympanic membrane serves as a critical protective barrier. It shields the sterile, delicate structures of the middle ear, such as the auditory ossicles, from bacteria, water, and foreign objects that could enter from the outside world. This protective function is essential for preventing infections and damage.
8. How does air pressure, like on a plane, affect the tympanic membrane?
The tympanic membrane is sensitive to changes in air pressure. Normally, the pressure on both sides is kept equal by the Eustachian tube. During a flight or scuba diving, the outside pressure can change rapidly, creating a pressure difference that pushes or pulls on the eardrum, causing discomfort or a 'popping' sensation. Actions like swallowing or yawning help open the Eustachian tube to equalise this pressure and relieve the stress on the membrane.
