Small fistulæ are to be closed bilaterally in an antero-posterior line(..)
1917, Louis Adolph Merillat, Fistula of the Withers and Poll-Evil, page 5
There are several reasons why a manual on this disease should be a part of the veterinary literature of the day, the chief one being that fistula of the withers is a very prevalent disease of horses and thus exacts a big toll from the horse industry.
Fistulas are abnormal communications between two epithelialized surfaces. The causes of enterocutaneous fistulas can be remembered using the mnemonic FRIEND: Foreign body, Radiation, Inflammation/Infection/Inflammatory bowel disease, Epithelialization, Neoplasm, and Distal obstruction. Fifteen to twenty-five percent of enterocutaneous fistulas arise spontaneously as in, for example, Crohn's disease or cancer.
2008, Sylvia Escott-Stump, Nutrition and Diagnosis-related Care, page 405
An intestinal fistula is an unwanted pathway from intestines to other organs (e.g., the bladder).