TDK conference 2021

The anatomy of the equine vascular system has been the subject of numerous works, but there is a lack of detailed knowledge about the structure and precise location of the individual segments of the vascular network. The jugular vein, which is of major importance in equine medicine, is the first and most common intravenous access route for the treatment of horses with medication, blood sampling, etc., yet very little is known about the various parameters such as the length of the vein, the number, location and size of the valves in it. In our post-mortem examinations, we dissected the bilateral jugular veins of 25 horses of different ages, sexes and body weights. We used a uniform procedure for each horse, focusing on the length of the veins, the number of valves in them and their location within the vein. The information from the dissections showed that although the veins of each individual varied in length as a function of body weight, no significant differences were found in the number and location of the valves. It was also found that, although the statistics support the experience that intravenous interventions in horses should be performed in the upper third of the jugular vein, there are still differences. From the information obtained from the 25 cadavers studied, we found that the number of valves in the jugular veins of horses ranges from 2 to 7. Based on the values calculated from the autopsy data, the mean number of venous valves in the right jugular is 3.94, and 3.4 in the left. This means four valves on the right and three on the left, with the same median value. For the right veins, 44% of the right veins had 3 valves , 32% of the left veins had 3 valves .

An important objective of our research was to map the location of the venous valves within the jugular, with particular attention to the location of the "first" valve closest to the truncus lingofacialis, as this is of most practical importance. The average length of the post-mortem dissected veins on the right side is 62.24 cm and the first valve is 19.88 cm, while the average length of the left side is 62.32 cm and 25 cm. Our results support the current preferred location of the jugular puncture, but it is important to point out that the number and location of the valves varies widely, with valves closer to the lingofacial truncus in almost 50% of the veins studied, and the first valve being located within 10 cm of the vein bifurcation in 10% of the 50 veins studied.

The practical aim of our studies is to reduce the risk of thrombophlebitis cases, which are often a serious complication of equine jugular vein cannulation.