Aditus ad antrum

Aditus to mastoid antrum
The medial wall and part of the posterior and anterior walls of the right tympanic cavity, side view.
Coronal section of right temporal bone
Details
Identifiers
Latin	Aditus ad antrum mastoideum
Dorlands /Elsevier	a_16/12113263
TA	A15.3.02.021
FMA	56797
Anatomical terminology []

The aditus to mastoid antrum (otomastoid foramen or entrance or aperture to the mastoid antrum) is a large irregular cavity that leads backward from the epitympanic recess into a considerable air space named the tympanic or mastoid antrum.

The antrum communicates behind and below with the mastoid air cells, which vary considerably in number, size, and form; the antrum and mastoid air cells are lined by mucous membrane, continuous with that lining the tympanic cavity.

On the medial wall of the entrance to the antrum is a rounded eminence, situated above and behind the prominence of the facial canal; it corresponds with the position of the ampullated ends of the superior and lateral semicircular canals.

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)