The<unk>  to the<unk>  is a large irregular aperture, which leads backward from the epitympanic recess into a considerable air space, named the tympanic or mastoid<unk> .
The<unk>  communicates behind and below with the mastoid air cells, which vary considerably in number, size, and form; the<unk>  and mastoid air cells are lined by mucous membrane, continuous with that lining the tympanic cavity.
On the medial wall of the<unk>  to the<unk>  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.
Entrance to the mastoid antrum
Vocal resonation
Acoustic neuroma causes
Mastoiditis pathophysiology
Tree in bud
Mastoiditis causes
Epiglottitis causes
Median aperture