Tympanic membrane (eardrum)


A thin, cone-shaped membrane that separates the external ear from the middle ear.

The eardrum transmits sound from the air to the ossicles inside the middle ear, and then to the oval window in the fluid-filled cochlea.

It ultimately converts and amplifies vibration in air to vibration in fluid.

The malleus bone bridges the gap between the eardrum and the other ossicles.

Rupture or perforation of the eardrum can lead to conductive hearing loss.

Collapse or retraction of the eardrum can also cause conductive hearing loss.

There are two general regions of the tympanic membrane: the pars flaccida (upper region) and the pars tensa.

The pars flaccida consists of two layers.

The pars flaccida is fragile, and is associated with eustachian tube dysfunction and cholesteatomas.

The larger pars tensa region consists of three layers.

The larger pars tensa layers are skin, fibrous tissue, and mucosa.

It is strong, and is associated with perforations.

The pars tensa forms most of the tympanic membrane.

The pars tensa periphery is thickened to form a fibrocartilaginous ring called the anulus tympanicus.

The central part of the pars tensa is tented inwards at the level of the tip of malleus and is called the umbo.

A cone of light can be seen radiating from the tip of the malleus to the periphery in the antero-inferior quadrant.

The pars flaccida is situated above the lateral process of the malleus between the notch of Rivinus and the anterior and posterior malleal folds.

The pars flaccida appears slightly pinkish.

The tympanic membrane is superiorly related to middle cranial fossa.

The tympanic membrane is posterior to the ear ossicles and the facial nerve, and is inferiorly to the parotid gland and anteriorly to the temporomandibular joint.

The umbo is the most depressed part of the tympanic membrane.

The manubrium of the malleus is attached to the medial surface of the membrane as far as its center, which it draws toward the tympanic cavity.

The lateral surface of the membrane is concave, and the most depressed part of this concavity is named the umbo.

Rupture of the ear drum can occur in blast injuries, but also during air travel, usually when the congestion of an upper respiratory infection has prevented equalization of pressure in the middle ear, in sport and recreation, such as swimming, diving with a poor entry into the water, scuba diving and martial arts.

80% to 95% have recovered completely from rupture of the eardrum without intervention in two to four weeks.

Eardrum rupture may be associated with short-lived hearing loss and tinnitus, and vertigo.

Some bleeding from the ear canal may occur if the eardrum has been ruptured.

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