This material must not be used for commercial purposes, or in any hospital or medical facility. Failure to comply may result in legal action. Medically reviewed by Drugs. Last updated on Jun 19, Anorectal abscess and anal fistula are conditions that often occur together. An anal fistula is an abnormal tunnel from the anus or rectum to the skin or another organ.
Rectum - Perianal Fistulas
The Radiology Assistant : Rectum - Perianal Fistulas
An anorectal or anal fistula is an abnormal, infected, tunnel-like passageway that forms from an infected anal gland. Sometimes an anal fistula works its way from an internal gland to the outside of the skin surrounding the anus. On the skin, this looks like an open boil. Usually the condition starts with an anal abscess, filled with pus. Even with treatment to drain the abscess, a persistent tunnel can develop between the infected area and the surface of the skin.
The anatomical anal canal extends from the perineal skin to the linea dentata. Surgically, the anal canal extends from the perineal skin to the anorectal ring. This is the circular upper border of the puborectal muscle which is digitally palpable upon rectal examination. The anorectal ring lies approximately ,5 cm above the linea dentata.
The anal canal is the end portion of the intestinal tract. It includes the rectum and anus. Sometimes, an abnormal passage forms from the anal canal to the skin near the anus. This is called an anal fistula. Anal fistulas can also form from the anal canal to other organs, such as the vagina or urinary tract.