Home > Encyclopedia of Medicine > Mastoiditis

Definition

Mastoiditis is an infection of the spaces within the mastoid bone. It is almost always associated with otitis media, an infection of the middle ear. In the most serious cases, the bone itself becomes infected.

Description

The mastoid is a part of the side (temporal bone) of the skull. It can be felt as a bony bump just behind and slightly above the level of the earlobe. The mastoid has been described as resembling a "honeycomb" of tiny partitioned-off airspaces. The mastoid is connected with the middle ear, so that when there is a collection of fluid in the middle ear, there is usually also a slight collection of fluid within the airspaces of the mastoid.

Mastoiditis can range from a simple case of some fluid escaping into the mastoid air cells during a middle ear infection, to a more complex infection which penetrates...