What is the anus?

The anus is an organ that is at the end of the digestive tract below the rectum. It consists of two sections: the anal canal and anus (or anal verge). The anal canal is a structure of 3-4 cm in length that lies between the anal sphincter (one of the muscles that control bowel movements) just below the rectum and the anal verge which represents the transition point between the tract tract and the skin on the outside of the body. Muscles in the anal canal and anus control passage of stool from the rectum to outside the body.