A partial situs inversus of the large intestine of a horse.

This research article describes the anatomical exploration of a horse with a rare congenital anomaly called partial situs inversus, where parts of the large intestine were found in mirror-image positions from their typical location.

Case Overview

• The study focuses on the dissection of a 15-year-old mare that had been embalmed. The horse was in good physical state and weighed approximately 550 kilograms. The anatomical exploration revealed a partial situs inversus of the horse’s large intestine, a very infrequent condition.

Dissection Process

• Initial observation was made with the animal’s organs (viscera) in their natural positions within the body. Organs such as the intestines, stomach, spleen, liver, pancreas, and kidneys were then removed along with part of the abdominal aorta.
• Documentation of the anomaly included photographs of the organs in situ and post removal.
• The digestive canal was cleansed of contents before a detailed inspection was done. The specimen was preserved in a 10 percent formalin solution for further observation and analysis.

Historical Cases of Situs Inversus

• The condition of situs inversus, where certain organs are positioned mirror opposite from normal, is a rare congenital condition in domestic animals. This document refers to past reports of this condition, indicating two instances of complete situs inversus in horses as well as similar conditions in cattle.

In Situ Observations

• Despite the presence of partial situs inversus, several organs including the liver, pancreas, stomach, spleen, duodenum and kidneys maintained their standard anatomical positions. This contributed to the diagnosis of partial rather than complete situs inversus in this case.