Infections in the middle ear can easily spread into the mastoid area via the aditus ad antrum and mastoid antrum.

The endoderm lines the future auditory tube (Pharyngotympanic " Eustachian " tube), middle ear, mastoid antrum, and inner layer of the tympanic membrane.

In the temporal bone, between the posterior wall of the external acoustic meatus and the posterior root of the zygomatic process is the area called the suprameatal triangle, suprameatal pit, mastoid fossa, foveola suprameatica, or Macewen's triangle, through which an instrument may be pushed into the mastoid antrum.

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.