Where is the external anal sphincter located?

　　The external anal sphincter is located in the subcutaneous tissue around the anus and on both sides of the anal canal. It connects superiorly with the internal anal sphincter and extends inferiorly to the anal margin, encircling the entire anal canal. It is an important striated muscle responsible for controlling anal closure and defecation. If symptoms such as perianal pain, fecal incontinence, or muscle weakness occur, prompt medical attention is recommended.

　　Anatomically, the external anal sphincter can be divided into three parts: the subcutaneous portion, superficial portion, and deep portion. The subcutaneous portion lies beneath the skin surrounding the anus and is relatively superficial; the superficial portion lies deeper than the subcutaneous part and originates from the coccyx; the deep portion surrounds the upper part of the anal canal and connects laterally with the internal anal sphincter. These three parts work together to regulate anal function.

　　Its primary function is to control defecation through contraction and relaxation. Normally, it remains contracted to maintain anal closure and prevent leakage of stool or gas; during defecation, it relaxes in coordination with the internal anal sphincter and pelvic floor muscles to facilitate smooth bowel movements, playing a crucial role in maintaining normal bowel function.

　　In daily life, maintaining regular bowel habits and avoiding prolonged squatting can help prevent excessive stretching of the muscles. Increasing dietary fiber intake keeps stools soft and reduces straining during defecation. Performing Kegel exercises regularly can also strengthen the contractile ability of the external anal sphincter.