The anus is the end of the digestive tract, where stool comes out of the body. It consists of a muscular ring called a sphincter that opens during a bowel movement to allow stool to pass through, as well as flat cells that line the inside of the anus. The mucous lining in the anus secretes mucus to lubricate the passage and help stool pass smoothly through. The anus plays an important role in bowel movements, as nerves and muscles surrounding it coordinate to tell you when you need to poop, while allowing you to hold it in until you’re able to reach a toilet. When you’re ready, these nerves and muscles coordinate again to push poop out of your body.
There is no specific difference between the anatomy of the anus in males and females. However, anorectal malformation (ARM), also called imperforate anus, is a condition where a baby is born with an abnormality of the anal opening. This defect happens while the baby is growing during pregnancy, and it can happen in both males and females. In a baby with anorectal malformation, the anal opening can be too small, in the wrong place, or can open into another organ inside the body such as the urethra, vagina, or perineum. Girls with anorectal malformations can have changes with their female anatomy, which can cause issues if left untreated.
