Configurations of Incudostapedial Joint Surface, An SEM Study

Abstract

There are few studies regarding the normal incudostapedial joint surface at the SEM level in dogs; therefore, in the present study we studied the normal morphology of the incudostapedial joint surface using SEM. The animals were anesthetized intravenously with Ketamine + Xylazine (5.2 mg/kg) and perfused with 2.5% glutaraldehyde in 0.1 M sodium phosphate buffer at pH 7.2 via left ventricle. Middle ear ossicles, the incus and stapes were processed using routine histological procedures for SEM studies and examined under a Philips 505 type SEM. The articular surfaces of incus and stapes had similar configuration and micromorphology. Articulation surface of the incus had small, spherical processes formed column-like structures lying in homogenously parallel fashion; the cartilage covering the articulation surface of the incus was present deep to these processes. The capsule of the incudostapedial joint was separated from the functional joint surface via a deeply lying sulcus. In contrast to incudomalleal (IM) joint, homogenously arranged and well formed controcytes and collagen fibers in the IS joint suggests that the ability of the IM joint to regulate the waves and strength of the sound arriving the IS joint. A comparative SEM studies of IM and IS joints will facilitate the understanding of the morphological changes during disease and aging.