epitympanic recess

The epitympanic recess is a hollow located on the superior/roof aspect of the middle ear.

It opens in front into that portion of the tympanic cavity which is known as the attic or epitympanic recess.

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