Mastoid antrum

Dr Henry Knipe and Dr Daniel J Bell et al.

The mastoid antrum (or tympanic antrum) is an air space (up to 1 cm in size) lying posterior to the middle ear and connected to it by a short passageway, the aditus ad antrum. The superior wall or roof of the mastoid antrum is known as the tegmen mastoideum, which continues anteriorly as the tegmen tympani.

Peripherally the antrum intercommunicates with multiple, variably-sized, smaller air spaces extending down to the tip of the mastoid process, the mastoid air cells.

The inner surface of the antrum is covered by a mucous membrane, which is in continuity with that of the middle ear. 


Developmentally the mastoid antrum is already at its adult size at birth.

Anatomy: Head and neck

Anatomy: Head and neck

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Article information

rID: 64014
Section: Anatomy
Tag: refs
Synonyms or Alternate Spellings:
  • Tympanic antrum
  • Aditus ad antrum
  • Mastoid antra

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