sphincter ani externus
Quick Summary
The sphincter ani externus is a ring-like muscle that surrounds the anal opening and, through its normal contraction, keeps it closed. This muscle is composed of striated muscle and is under voluntary control. It is one of several sphincter muscles in the human body, which are responsible for closing bodily passages or openings. Other examples include the sphincter pylori in the stomach and the sphincter urethrae, which controls urination. The anal canal, where the sphincter ani externus is located, connects the rectum to the outside of the body and plays a crucial role in the controlled elimination of feces.123
Ask Britannica AI about this topic
Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.
