The external anal sphincter is made up of three parts.

Three parts of the External Anal Sphincter:

• The Levator ani contributes to the puborectalis, which is continuous with the external anal sphincter.

• Tube within a tube which is the inner tube consisting of internal sphincter (smooth muscle)

• Tube within a tube which is the outer tube consisting of puborectalis/external sphincter complex (skeletal muscle)

The anorectal muscles such as the levator ani are a major support to the pelvic floor. The puborectalis forms the muscular sling around the anorectal junction. It controls the anorectal angle and therefore plays an important role in fecal continence and defecation (the evacuation of feces from the bowel). The external anal sphincter is composed of striated muscle and is divided into three parts which are known as the subcutaneous, superficial, and deep external sphincters. The internal sphincter is composed of smooth muscle while the external sphincter is made of striated muscle which have nerves called the pudendal nerves that allow for the voluntary control of these muscle layers that make up the external anal sphincter.