An anal sphincter is a group of muscles at the end of the rectum that surrounds the anus and controls the release of stool, thereby maintaining continence. There are two sphincter muscles: one is internal and one is external. The external anal sphincter muscle helps maintain continence and keep stool in the rectum. If there is a loss of muscle control in the sphincter, fecal incontinence may occur. The inner muscle is not under voluntary control but rather is controlled by the autonomic nervous system.
Overview of the Anal Sphincter
Anal Sphincter Injury | Pelvic Floor Center
When a tubular organ or blood vessel becomes excessively narrow such that it can no longer perform as nature intended, it is a condition referred to by physicians as stenosis. Anal stenosis, also known as an anal stricture, is the narrowing of the anal canal, located just before the anal sphincter. The anal sphincter is a complex part of the body that maintains a seal that can be opened to discharge body waste. It is strong enough to restrict the passage of any fecal material but sensitive enough to differentiate between solid, liquid, and gas. There are actually two anal sphincter muscles … internal and external. The internal anal sphincter is a thin, white muscle wrapped around the anal canal. The internal sphincter contracts during rest and sleep, and keeps small amounts of liquid and gas from escaping unexpectedly.
Internal anal sphincter
Jump to navigation. A sphincter injury refers to a tear or damage to the muscle that surrounds the anal canal. These muscles are used to control bowel movements. Damage to one or both of these muscles can result in the decreased ability to control bowel movements and can contribute to symptoms of accidental bowel leakage.
To evaluate anal sphincter anatomy using three-dimensional ultrasonography 3-DAUS in incontinent women with vaginal delivery, correlate anatomical findings with symptoms of fecal incontinence and determine the effect of vaginal delivery on anal canal anatomy and function. A control group comprising asymptomatic nulliparous was included. Of the 62, 49 had fecal incontinence and 13 were asymptomatic. Those with a vaginal delivery and intact sphincters had a shorter anterior EAS and longer gap than nulliparous.