Fistula-in-ano is a medical term used for anal fistula. Fistula means an abnormal connection between any two parts of the body. Fistula-in-ano is an abnormal connecting tunnel between the skin and the muscular opening of the anus. The anus is the end of the digestive tract from where the solid waste is passed out from the human body. The anal fistula occurs due to an infection of the anal gland. This infection may result in an abscess.

The fistula is an abnormal opening under the skin which connects to the anus. This may get infected with bacteria and viruses. Also, there are chances of recurrent infection due to abnormal openings present under the skin near the anus. In simple words, Fistula-in-ano- is an abnormal opening present in the anus that may get infected, leading to pustular discharge and pain.

Fistula-in-ano is a surgical condition that may get better with homeopathy on many occasions if not all.

There are several types of anal fistulas, and they are classified based on their anatomy and the path the tunnel takes. Here are some common types:

1) Intersphincteric Fistula: This type of fistula runs through the internal sphincter muscle of the anus. It's not very complicated compared to other kinds.

2) Transsphincteric Fistula: The tract of this fistula goes through both the internal and external sphincter muscles. It extends from the inside of the rectum or anal canal to the skin around the anus.