The Urethral Rhabdosphincter, Levator Ani Muscle, and Perineal Membrane: A Review
Figure 5
Levator ani insertion to the rectum seen in a frontal section of a 91-year-old man. Panel (a) (azan staining) displays the covering fasciae and intramuscular tendons (stars) of the levator ani (LA) converging into the longitudinal muscle layer of the anterior wall of the rectum (REC). Both striated and smooth muscle fibers are red, while connective tissues (collagen and elastic fibers) are dark blue. The definite fibrous connection between the levator ani and rectum is quite different from that between the levator and urethra. Panel (b) (nerve mapping according to S100 protein immunohistochemistry) exhibits a level 5 mm anterior to panel (a). The rectourethralis muscle (RUM) provides one of major pathways of the cavernous nerve from the periprostatic region to the penile hilum. These panels were prepared at the same magnification (scales bars: 10 mm in panel (a)). BP: bulbus penis; BS: bulbospongiosus muscle; DTP: deep transverse perineal muscle; IC: ischiocavernosus muscle; PR: prostate.
