The tympanic membrane, or eardrum, works by converting sound waves from the outer ear into mechanical vibrations that can be processed by the middle and inner ear. When sound waves enter the ear canal, they strike the tympanic membrane, causing it to vibrate like a drumhead. These vibrations are then transmitted to the tiny bones (ossicles) of the middle ear, beginning with the malleus, which is attached to the membrane's inner surface. The ossicles amplify and convey these vibrations to the cochlea in the inner ear, where they are transformed into nerve signals for the brain to interpret as sound
. Structurally, the tympanic membrane is a thin, oval, semi-transparent tissue composed of three layers: an outer epidermal layer continuous with the skin of the ear canal, a middle fibrous layer providing strength and stiffness, and an inner mucosal layer continuous with the middle ear lining. Its shape is conical, with the apex (umbo) pulled inward by the malleus, creating tension that optimizes vibration
. The membrane also serves as a protective barrier between the outer and middle ear, helping to prevent infection and damage. It is supplied by blood vessels and innervated by several cranial nerves, which contribute to its sensitivity and reflexive responses. Muscles such as the tensor tympani can adjust the tension of the membrane to protect the inner ear from loud noises through the acoustic reflex
. In summary, the tympanic membrane works by:
- Receiving sound waves and vibrating in response.
- Transmitting these vibrations to the middle ear ossicles.
- Serving as a protective barrier between outer and middle ear.
- Adjusting tension via muscular reflexes to protect the ear from loud sounds
