H80.9: Otosclerosis, unspecified

Areas of your middle ear or inner ear have hardened.

The precise cause of this disorder is unknown.

The ear is a sensory organ that is used to hear and to maintain one's balance. There are 3 different areas in the ear: the outer ear, middle ear and inner ear. The middle ear begins behind the eardrum. It consists of the air-filled tympanic cavity and the 3 ossicles. The actual hearing organ, the cochlea, is in the inner ear. The cochlea consists of a channel of bone in a spiral, like a snail. Inside the cochlea are the sensory cells for hearing. The inner ear connects to the brain via the auditory nerve.

Noise and sounds from the environment reach our ears as sound waves. When the sound waves meet the eardrum, they make it vibrate. These vibrations are transmitted via the ossicles to the cochlea, getting amplified in the process. In the cochlea the sensory cells convert the vibrations to electrical signals. These signals then pass via the auditory nerve to the brain, where they are perceived and processed. When areas in the middle ear or inner ear have hardened, one's hearing might be restricted. One may also perceive a noise in one's ear. This is called tinnitus.