Mastoid air cells

The mastoid air cells (cellulae mastoideae) represent the pneumatization of the mastoid part of the temporal bone and are of variable size and extent.

Gross anatomy

At the superior and anterior part of the mastoid process the air cells are large and irregular and contain air, but toward the inferior part they diminish in size, while those at the apex of the process are frequently quite small and contain marrow. Occasionally, they are entirely absent.

Mastoid air cells communicate with the middle ear via the mastoid antrum and the aditus ad antrum.

The mastoid air cells are traversed by the Koerner septum, a thin bony structure formed by the petrosquamous suture that extends posteriorly from the epitympanum, separating the mastoid air cells into medial and lateral compartments.

Related pathology

• otomastoiditis
  • acute otomastoiditis
    • subperiosteal abscess
      • coalescent mastoiditis
  • chronic otomastoiditis
• cholesterol granuloma

See also

• mastoid air cell opacification