FISTULA
A fistula in ano (anal fistula) is a track running from the skin on the outside of the buttock or anal area to the inside of your bottom.
On the surface of the skin around the anus there may be one or more holes (external openings). There are different types fo fistulae from simple to complex branching ones.
Some fistulae may run through the sphincter muscles (the ring of muscles that open and close the anus and are responsible for continence).
Each fistula is very unique and treatment is very individual.
Most fistula occur as a result of abscess (collection of pus) under the skin. It is usually secondary to blockage and infection of the glands around the anal canal.
They usually present as a painful lump.