QS Study

The tympanic cavity is a biconcave space with a vertical and anteroposterior diameter of about 15 mm and transverse diameter from 2 mm to 6 mm. It is a small cavity surrounding the bones of the middle ear. The main function is to convey sound from the air of the outside acoustic meatus to the fluid in the labyrinth.

Tympanic Cavity 1

Fig: Tympanic Cavity

Boundary

The tympanic cavity has six walls. It is located medially to the tympanic membrane. It contains three small bones known as the auditory ossicles: the malleus, incus, and stapes. They transmit sound vibrations through the middle ear.

Roof: It is formed by a thin bone from the petrous part of the temporal bone. The roof is formed by tegmen tympani which is a thin plate of bone separating the cavity from the middle cranial fossa. It separates the middle ear from the middle cranial fossa.

Floor: It is known as the jugular wall. It is formed by a thin plate of bone separating the cavity from the cavity from the jugular bulb. It consists of a thin layer of bone, which separates the middle ear from the internal jugular vein

Lateral wall: It is made up of the tympanic membrane and the lateral wall of the epitympanic recess. It is mainly formed by the tympanic membrane and partly by bone above, behind and below.

Anterior wall: It is a thin bony plate with two openings; for the auditory tube and the tensor tympani muscle. It is very narrow. It separates the middle ear from the internal carotid artery.

Medial wall: If separates the middle ear from the inner ear. It contains a prominent bulge, produced by the facial nerve as it travels nearby. The most obvious feature is the promontory.

Posterior wall: It consists of a bony partition between the tympanic cavity and the mastoid air cells. It is formed by the deeper part of the posterior tympanum.

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