Observations of the anterior epitympanic recess in the human temporal bone.

The structure of the anterior epitympanic recess was examined in 50 human temporal bones. The recess was found in 48 temporal bones (96%) and showed three different structural types. In type A, the least developed type (38%), a main cavity is seen above the tensor tympanic fold. The recess is divided into two cavities by the tensor tympanic fold, which stretches to the anterosuperior tympanic tegmen in type B, the intermediate type (40%). The tensor tympanic fold is fused with the superior mallear fold in type C, the best-developed type (18%), with the recess being contiguous with the eustachian tube. The shape of the anterior epitympanic recess is influenced by the ratio between the cavities above and below the tensor tympanic fold, ie, by the embryologic development of the saccus anticus and the anterior saccule of the saccus medius. The structural variations in this recess must be kept in mind during the surgical management of middle ear diseases.