Mastoid Processes: Anatomy, Air Cells, and Clinical Relevance

Location & Structure

Paired bony prominences on the temporal bone, posterior to the external auditory meatus (behind the ears).

Internal Features

• Mastoid Air Cells: Honeycomb of air‑filled spaces continuous with middle ear cavity; aerate the middle ear, equalize pressure.
• Mastoid Sinuses (Venous): Drain into sigmoid sinus.

Clinical Significance

• Mastoiditis: infection of air cells (complication of otitis media).
• Surgical landmark for posterior cranial fossa approaches.