The middle ear is an air-filled space located behind the eardrum. The Merck Manuals Medical Library describes the middle ear as containing three tiny bones, called ossicles. These bones transmit sound vibrations from the eardrum to the inner ear. Therefore, the middle ear plays a critical role in hearing. Problems of the middle ear range from common and mild infections to complete hearing loss.
Otitis Media
This condition, commonly known as an ear infection, is an inflammation of the middle ear caused by viruses or bacteria. Any condition that causes inflammation or irritation, such as allergies or a cold, can make you more susceptible to an ear infection. Children are particularly susceptible, in part due to the short length and straight angle of a child's eustachian tube, which drains the middle ear.
Mastoiditis
The mastoid bone of the skull is found just behind the outer ear. This bone has a porous structure. Mastoiditis can occur if an infection, such as bacteria, spreads from an infected middle ear to the mastoid bone. This illness affects children more often than adults, although it is fairly uncommon, according to MedlinePlus.com.
Cholesteatoma
Recurrent ear infections and dysfunction of the eustachian tube can result in the growth of a sac behind the eardrum, reports the American Academy of Otolaryngology - Head and Neck Surgery. Repeated infections can create a vacuum in the middle ear, causing the eardrum to retract. This eventually leads to the formation of a cyst-like pouch that is filled with old skin cells and waste matter. Rarely, a cholesteatoma is present at birth.
Otosclerosis
This disorder is caused by bony overgrowth of one or more of the small bones in the middle ear. Usually the last bone in the chain, the stapes, is the one involved. When this happens, the bones of the middle ear are not able to vibrate. This reduces sound transmission, and causes hearing loss.
Barotitis Media
This condition can arise due to differences in air pressure on either side of the ear drum. If the eustachian tube is blocked from scarring or infection, air flow to the middle ear is interrupted. A bruised, or ruptured ear drum can result, states the Merck Manuals Medical Library.
