AN ANATOMICAL INTERPRETATION OF OUTER AND INNER MUSCLE BUNDLE GROUPS IN MALE PELVIC FLOOR MUSCLES

Abstract

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Background. Many findings of the connections among the perineal skeletal muscles in males have been reported recently. However, the detailed connections in the outer aspects have been still unclear. Aim. In the present study, we examined these muscles both from the outer and inner aspects minutely. Material and Methods. In the present study, we used sixteen pelvic halves from ten male cadavers (average 78 years old). The muscles of the pelvic floor and the perineal muscles were removed from the pelvis en bloc. The organs, connective tissues, vessels and nerves were carefully removed to examine the connections among the muscles. Results and Discussion. On the lateral aspects of the perineal muscles, outer muscle bundles of external anal sphincter (EAS) connected with those of the bulbospongiosus (BS). The superficial transverse perineal muscle adjoined with the outer bundles of EAS and BS. Outer muscle bundles of the levator ani (LA) conneted with the posterior part of BS, and with the superior part of EAS. Outer bundles of EAS with a part of LA posteriorly gathered together to attach to the anococcygeal ligament. On the medial aspects, inner parts of EAS and BS were separated each other. The deep muscle bundles of EAS together with the bundles of LA formed the circular sphincter muscle. Conclusions. The perineal muscles were classified into outer and inner groups. The muscle bundles of the outer group were connected each other, while those of the inner group were divided into the anterior muscle (BS) ad the posterior muscle (EAS).