The Urethral Rhabdosphincter, Levator Ani Muscle, and Perineal Membrane: A Review

Figure 8

Frontal sections in an 83-year-old woman. Panels (a), (b), (d), and (e): HE staining; panel (c): aldehyde fuchsin staining (elastic fibers, violet). In panels (a) and (c), elastic fibers between the muscle fibers of the rhabdosphincter (RS) join to provide a thick fascial structure, the perineal membrane (arrows in panel (a)). The levator ani is attached to the upper aspect of the membrane. Panel (b), 25 mm behind panel (a), includes the posterior end of the vestibular bulb (VB). Part of the rhabdosphincter, the urethrovaginal sphincter (UVS), extends in and along the perineal membrane in panel (b). Scale bars: 10 mm in panels (a) and (b); 1 mm in panels (c), (d), and (e). BS: bulbospongiosus muscle; CC: crus clitoris; CU: compressor urethrae; DTP: deep transverse perineal muscle; IC: ischiocavernosus muscle; IRF: ischiorectal fossa; VAG: vagina; VB: vestibular bulb.