What is Anal Fistula?

An anal fistula is an abnormal inflammatory tract between the anal canal and skin surface. A fistula is usually formed by the repeated filling of an abscess with fluid contents of some body cavity.


Types of fistula include:

  • Blind (open on one end only, but connects to two structures) 
  • Complete (has both external and internal openings) 
  • Horseshoe (connecting the anus to the surface of the skin after going around the rectum) 
  • Incomplete (a tube from the skin that is closed on the inside and does not connect to any internal structure)