Instances of the anomalous exit of urine caused by congenital malformation or fistulous connections are mentioned in another chapter.
"Anomalies and Curiosities of Medicine" by George M. Gould
There is a gradual increase in the severity of the symptoms, and later fistulous openings appear in the hollow of the heel.
"Diseases of the Horse's Foot" by Harry Caulton Reeks
Probing will now disclose a fistulous tract leading to the bottom of the diseased tissues.
"Special Report on Diseases of the Horse" by United States Department of Agriculture