Semimicroscopical observations on the crista stapedis

Adult and fetal human stapes were removed by means of the stereoscopic microscope in order to compare the size of the lamina or crista that joins the crura of the stapes and rests in the lateral aspect of the basis. 65 out of 110 specimens showed cristae of different sizes, whereas the remaining 35% did not possess this structure. The cristae were classified into large, medium-sized and rudimentary. Several incomplete or irregular structures were also found. The cristae or laminae divide the lateral aspect of the base into two fossae: a small upper one and a large lower one, although several variations were found. An edge of the pillar groove was usually continuous with the cristae; however, compact pillars were found at the point where they reach the base, where the cristae orginates. Asymmetrical cristae and changes in the general shape of the stapes were found in several specimens. Two ossicles showed crista with orifices due to resorption or to the passage of vessels.