Anal Fistulas

An anal fistula is an abnormal connection between the epithelialised surface of the anal canal and (usually) the perianal skin.

Anal fistulae originate from the anal glands, which are located between the two layers of the anal sphincters and which drain into the anal canal. If the outlet of these glands becomes blocked, an abscess can form which can eventually point to the skin surface. The tract formed by this process is the fistula.