Which organs are intraperitoneal? We've got the liver, the spleen, the stomach, the first part of the duodenum. We've got the jejunum and ileum. All these loops of intestine. Then the transverse colon is obviously intraperitoneal. We've got the sigmoid colon, which is intraperitoneal. And the superior parts of the rectum are also intraperitoneal.
The retroperitoneal organs are the kidneys at the back. You can see the kidneys here. And the adrenal glands which sit on top are retroperitoneal. We've got the head and the body of the pancreas, which are retroperitoneal (the tail is actually intraperitoneal). And then we've got the second to fourth parts of the duodenum, so the bits between the duodenojejunal flexure. We’ve got the second to fourth parts of the duodenum which are retroperitoneal. And then you've got the ascending and descending parts of the colon, which are retroperitoneal.