In this video I will show you the peritoneal structures in reality. Let's first orient ourselves. You see an opened abdomen. The abdominal wall has been removed and the body has been prepared such that the intestines are all well accessible. The head is to the right, and the legs are to the left. Here are the anterior superior iliac spines, the liver, and now we lift up the diaphragm. And this is the falciform ligament. Below the liver, we find the stomach. And hanging downward from the stomach is the greater omentum, and behind that is the transverse colon. The greater omentum has been detached off the transverse mesocolon in this body. I'm now going to lift up the greater omentum. It is connected to the greater curvature of the stomach, so I now also lift up the stomach. You look at the backside of the stomach now and that gives us a view inside omental bursa that's open now. Following onward from the stomach is the duodenum. Here's the pancreas from the head to the tail, running in the direction of the spleen. At the lower border of the pancreas, I find the brim remnants of the peritoneal membrane that was the backside of the sac of of dorsal mesentery that formed the greater omentum. The front side of the sac hung downward from the greater curvature of the stomach. And from the bottom of the sac the peritoneum curves upward again to the pancreas. The front and the back layers of the sac adhered to each other and the sac got occluded. The greater omentum was formed. One can imagine that this back layer remnant was connected to the greater omentum. One never succeeds, at least I never succeeded, in detaching the greater omentum from the transverse mesocolon with the front and back sides of this original sac intact. Part of the back layers probably remained attached to the transverse mesocolon, and one breaks through this back layer and thus enters and opens the omental bursa. Next we see the transverse colon with its transverse mesocolon. You see how the transverse colon is suspended from it. There's a beautiful marginal artery in it. And we can clearly see that the transverse mesocolon has been detached from the greater omentum. These two once were adhered to each other. This was the back wall connected to the front wall in this way. This was a hole that formed the sac. You might wonder why the transverse colon hangs so far downward, nearly reaching the pubic bone. In the atlases, the transverse colon is always depicted as crossing the abdomen nearly horizontally. But in fact, approximately one-third of people has a transverse colon that hangs downward very far, so this is completely normal. If we flip up the transverse colon and mesocolon, then we find underneath it the whole bundle of small intestines. Surrounding that we see the ascending colon, the transverse colon, and the descending colon. The descending colon is suspended by the descending mesocolon. These have been detached from the back wall here, rendering the descending colon mobile again, as it once was in the embryonic phase, before it adhered to the back wall. We also clearly see the parietal peritoneum of the abdominal side wall. This peritoneum is the continuation of the parietal peritoneum of the abdominal back wall. And behind that are the retroperitoneal organs. I return the descending colon to its place. We can now follow the mesentery and see that it's one continuous hole. The descending mesocolon, the transverse mesocolon, the ascending mesocolon that has also been detached from the back wall, and it continues in the mesentery of the small intestines. So let's show it once more. All these mesenteries are continuous. This is the direction of the rotation that the intestines once made, and they pulled the mesenteries along with them. Now we can identify this point, the Treitz point, where the duodenum appears from the back and changes in the jejunum. I can lift up the whole package of small intestines, together with the ascending colon. And that gives us a view on the duodenum and on the point of Treitz where the small intestines arose from the back and became jejunum. I'll now return the intestines to its place. Then return the transverse colon. And finally return the greater omentum that was attached to it. We now have got original situation again. In this video, I demonstrated how the greater omentum can be detached from the transverse colon and mesocolon, how the ascending and descending mesocolons can be be detached from the back wall, how the mesenteries, in fact, are one continuum, and how the duodenum can be found crossing behind the adhesion area of the ascending colon and small intestines.