How'd I Do?

 The horse gut is an amazing and complex thing. They have a single stomach like us, although it's only partially glandular like ours. The real magic happens in their cecum and very long colons. They have a right ventral colon, a left dorsal colon, and a right dorsal colon, plus a regular colon called the descending colon. Their cecum is an enormous blind sac located between the small intestines and all of these colons. 

Depending on the particular pathologies involved, it can be kind of difficult to identify the various parts of the horse's gut during a necropsy. The best way is to remove the entire digestive tract from stomach down, cut all of the ligaments (thin sheets of tissue that hold it in a particular shape), and stretch it out. 

Yesterday I had a foal who died from not one but two intestinal ruptures. For accuracy in my report, I wanted to figure out exactly what parts were affected. Because everything in the foal's abdomen had been marinating in intestinal contents and bacteria for a couple of days, there was a lot of autolysis (post-mortem changes). And there was necrosis of various parts of his gut associated with ulcers and hemorrhage that preceded the two ruptures. Tissues were delicate and friable. Everything was coated in bits of partially digested feed and greenish, bloody fluid. 

We of course took pictures but those can be hard to interpret, and sometimes the techs don't get those loaded onto the server for a couple of days. After I had extricated his gut and stretched it out, I made a quick sketch, labeled some key bits, and marked the areas of the ruptures. Here's the result:

 

"Colon" is the descending colon, RDC is the right dorsal colon, PF is the pelvic flexure (a distinctive anatomical feature of the horse gut), "base cecum" is where the cecum opens into the right ventral colon, J is jejunum, D is duodenum, and "stom" is the stomach. That bit sticking off the stomach would be the esophagus. The heavy black bars are the two rupture sites.

Compare this to a diagram from one of my vet school textbooks:

 

I think I produced a real masterpiece!

Notice how I positioned the stomach to the right, descending colon to the left, the same way as in the picture. That's because we necropsy ruminants and horses from a left lateral position, meaning their left sides are down on the table. This creates the same right lateral view of the intestines as shown in the picture. I'm pretty sure I would struggle to identify things if I had to look at them from the left aspect. 

Consistency is important when doing necropsies. If we examine tissues in the same order every time, we are much less likely to miss problems.