Abstract 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, foveolasuprameatica, or Mac Ewen's triangle, through which an instrument may be pushed into the mastoid antrum..In the adult, the antrum lies approximately 1.5 to 2 cm deep to the suprameatal triangle. This is an important landmark when performing a cortical mastoidectomy. The triangle lies deep to the cymba conchae.The sex determination of unknown human skulls can be evaluated by using the measurement of the area formed by the xerographic projection of 3craniometric points related to the mastoid process: the porion, asterion, and mastoidale points.