Explore pelvic floor anatomy and function! The superficial layer: external anal sphincter muscle.
Dr. Sherine Aubert describes the external anal sphincter muscle, part of the superficial (or outermost) layer of the pelvic floor.
The external anal sphincter muscle is, as the name suggests, a sphincteric (constricts and relaxes to allow passage in or out) muscle. It encircles the anus, relaxing to allow stool or gas to pass. Its shape allows a puckering movement around the anus when we contract our pelvic floor muscles and a relaxation when we breath into our pelvic bowls.