Remember that the first fistula came about accidentally from a musket shot that left Sir. Alexis St. Martin with an opening in the stomach which never healed. Fistulas vary in size and location due to the purpose and shape of the patient (human or animal). For instance, a fistula can be used in colostomies in humans and also in the better understanding of digestion in ruminants. Similarly, when women and men get their ears pierced, the resulting hole in the ear can be called a fistula