Fistula in Ano
Fistula can be defined as an abnormal connection between anal canal and perianal skin. The fistulae are formed form the blockage of the anal glands that drain into anal canal leading to formation of abscess. If they are blocked for long time they lead to development of pus inside the fistula. Fistulae are very painful in nature and pus keeps draining from them causing a lot of discomfort.