n     Intersphincteric-Fistula tract passes between the two sphincters- 64%

n     Trans-sphincteric- Fistula tract crosses the two sphincters- 30%

n     Submusoal- Fistula tract passes between the sphincters and the mucosa of anus and rectum 5%

n     Extrasphincteric- Fistula tract goes beyond the sphincter- 1%

For practical purposes, Anal Fistula are 2 types- Low & High. Low Fistula are present in the lower part and do not extend up to the ano-rectal sling [ muscle layer responsible for continence (control on passage of motions)]. High fistula extend up to or beyond ano-rectal sling. Knowing the type of fistula is important because high fistula if not managed properly can be associated with incontinence.[loss of control on passage of motions]