What is the external anal sphincter?

The anal sphincter is a part of the anorectal ring, which is the muscle ring that controls anal defecation. It includes the puborectal muscle, levator ani muscle, internal anal sphincter and external anal sphincter. The

external anal sphincter can be divided into three parts from an anatomical point of view. The first part is the deep part of the external anal sphincter. The second part is the superficial part of the external anal sphincter. The lowest part is the subcutaneous part of the external anal sphincter. These three parts together form the external anal sphincter. Its contraction is controlled by the human body's consciousness and can be contracted and relaxed autonomously.