mastoid

The mastoid refers to the mastoid part of the temporal bone, a rounded projection located behind the ear. It contains a system of air-filled spaces called the mastoid air cells, which connect to the middle ear through the aditus ad antrum. The mastoid process provides attachment for several neck muscles, including the sternocleidomastoid, splenius capitis, and longissimus capitis.

The mastoid air cell system varies greatly among individuals and develops with age. In infancy the cells are few and poorly aerated, but pneumatization increases over childhood and adulthood. The air cells help with ventilation and drainage of the middle ear, and the extent of pneumatization can influence disease spread and imaging appearance.

Clinical relevance centers on mastoiditis, an inflammation or infection of the mastoid air cells that typically follows acute otitis media. Symptoms may include deep ear pain, redness and swelling behind the ear, fever, and tenderness. If untreated, complications can arise, including subperiosteal abscess, facial nerve palsy, meningitis, or intracranial extension. Management involves antibiotics, and surgical drainage or mastoidectomy may be necessary in refractory or complicated cases. Imaging, especially high-resolution computed tomography, is used to assess the extent of pneumatization and infection, while MRI can evaluate soft tissue involvement.

Etymology: the term mastoid derives from the Greek mastos, meaning breast or nipple, referring to the bone’s nipple-like projection.