The site of the mastoid process is directly behind and below the ear on the human skull. It is attached to the temporal bone and serves as an important site for muscle attachment.
The mastoid process is a conical or smooth pyramid shape and is usually larger in males than females. This difference is usually attributed to the larger size and corresponding strength requirements of three important muscles attached to the exterior. The interior contains air-filled sacs that are in direct contact with the inner ear. The term "mastoid" derives from the Greek word for "breast," referring to the shape of the bone.