Ischiocavernosus The structure indicated is the ischiocavernosus muscle. The ischiocavernosus muscle is one of three pairs of muscles in the superficial perineal pouch: Ischiocavernosus Bulbospongiosus Superficial transverse perineal muscles It originates from the inner aspect of the ischiopubic ramus and attaches on either side to the crura of the penis and clitoris. Origin: Ischiopubic ramus – internal aspect Insertion: Crus of penis and clitoris Action: Stabilise erect penis Innervation: Pudendal nerve Learn more about the pelvic floor in this tutorial