Musculus sphincter ani externus

The external anal sphincter (or sphincter ani externus ) is a flat plane of skeletal muscle fibers, elliptical in shape and intimately adherent to the skin surrounding the margin of the anus.IntestinesSchematic demonstrating the anatomy of hemorrhoids.Muscles of male perineum.Muscles of the female perineum.Sagittal (vertical) section of bladder, penis, and urethra. The external anal sphincter (or sphincter ani externus ) is a flat plane of skeletal muscle fibers, elliptical in shape and intimately adherent to the skin surrounding the margin of the anus.