The ear is the organ that is present for hearing in mammals; it also helps in balance. In mammals, it usually consists of three parts: inner ear, middle ear, and outer ear. The inner ear is present in the bony labyrinth, the middle ear consists of three ossicles and a tympanic cavity. The outer part is the visible one and consists of the ear canal and pinna.
In mammals and other tetrapods, the anatomy includes the eardrum that is also known as myringa or tympanic membrane. It is a thin and cone-shaped membrane that helps to separate the external ear. Tympanum function is to transmit the sound to the ossicles from the air. From the ossicles, the sound waves travel through the oval window in the fluid-filled cochlea. The sound gets converted and amplified.
Tympanic Cavity - Structure
The middle ear is situated in between the inner ear and the outer ear. It includes an air-filled cavity known as the tympanic cavity, three ossicles, attaching ligaments, oval, and round window. These three ossicles function together to receive, amplify and transmit the sound from the eardrum to the inner ear. These three ossicles include malleus, incus, and stapes, where the malleus acts as a bridge between the eardrum and the ossicles. The medial wall of the middle ear is formed by the lateral of the inner ear. This wall helps to separate the tympanic cavity from the inner ear.
The tympanic membrane is oriented in the anteroposterior, superoposterior, and mediolateral planes in an oblique form. The membrane’s superoposterior end lies laterally to the anteroinferior end. It is related to the middle cranial fossa superiorly, to the ossicles and facial nerve posteriorly, to the parotid gland inferiorly, and to the temporomandibular joint anteriorly.
The tympanic cavity has two regions, pars flaccida, and pars tensa. The pars flaccida lies above the lateral process of the malleus that is present in between the notch of the Rivinus and anterior and posterior to the malleable folds. It looks slightly pinkish in colour and has two layers. The pars tensa is larger and consists of three layers that include fibrous tissue, skin, and mucosa. The fibrocartilaginous ring is formed by the thick periphery it is known as the Gerlach's ligament or annulus tympanicus. The central umbo tents are present at the tip of the malleus and it is inward to its level. The middle fibrous layer consists of radial, circular, and parabolic fibres.
The sensation sent to the outer surface of the tympanic membrane is supplied by the nerve called auriculotemporal nerve. It is a branch of the mandibular nerve, it is contributed to the auricular branch of the vagus nerve, facial nerve, and glossopharyngeal nerve.
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Ear Membrane Damage
The hole or tear in the eardrum can rupture the eardrum or tympanic membrane. The membrane gets vibrated when the sound waves enter the eardrum and it travels to the middle ear. The ruptured ear membrane is also known as the perforated eardrum; sometimes this may cause permanent loss of hearing.
Other causes of hearing loss are:
1. Infection: In children, the common cause for the rupture of the eardrum is an infection, during which some fluids get accumulated at the back of the eardrum. This fluid buildup can increase the pressure that leads to breaking in the tympanic membrane.
2. Pressure Changes: Barotrauma occurs when the pressure that is present inside the ear is different from that of the pressure that is present outside the ear. These changes in the pressure can lead to damage to the tympanum ear damage. Some of the activities also can cause barotrauma that includes: driving at high altitudes, scuba diving, shock waves, and forceful or direct impact to the ear.
3. Injury: Another cause that can lead to the damage of the membrane is injury, the injury that occurs to the ear or sides of the head can cause damage to the eardrum. The injury can occur due to car accidents, getting hit to the ear, falling on the ear, or injury during sports. Inserting any object such as a pen, fingernail, or cotton swab can harm the eardrum. Damage to the ear can occur due to loud noises is known as acoustic trauma.
Symptoms and Treatment
The main symptom is pain, watery or blood or fluids filled with pus can drain from the infected or damaged ear. The damage that occurs to the middle ear can cause bleeding. The infections to the ear can be found in young children, people living in poor air quality, or with cold or flu.
Treatment given to the ruptured ear are as follows:
1. Patching: If the ear does not get repaired by itself then the doctor might suggest patching the eardrum. It involves placing a medicated paper patch on the tear. This patch helps the membrane to grow back.
2. Antibiotics: It helps to clear the infections, and also helps to prevent getting infected by the new infections. The medical advisor can suggest oral antibiotics or some medicated ear drops.
3. Surgery: To patch the hole present in the eardrum sometimes surgery is required. The surgical repair of the eardrum is known as tympanoplasty. This is done by grafting the hole with the tissue taken from another part of the body.
Along with these treatments some home remedies can help to relieve the pain, such as placing warm and dry compress on the ear can reduce the pain.
In mammals, the ear helps to balance and hearing. It has three regions: outer, middle, and inner ear. The medial wall of the middle ear separates the tympanic membrane from the inner ear. It is also known as the eardrum. The main function of this membrane is to help humans with hearing. When the sound waves reach this membrane it starts vibrating and these vibrations are sent to the inner ear.