Medical and health problems: Are omental cavity and omental sac (omental sac) the same concept?

The omental sac is a narrow space behind the omentum and stomach, also known as the small peritoneal cavity. The peritoneal cavity outside the omental sac is called the large peritoneal cavity. As a part of the peritoneal cavity, it is a flat and narrow sac, and its front wall consists of omentum, stomach, upper duodenum and the first two layers of omentum from top to bottom. The posterior wall is the peritoneum covering the pancreas, left adrenal gland and left kidney, and the posterior layer of transverse colon, transverse mesocolon and greater omentum. The upper wall is the caudate lobe of the liver and the peritoneum of diaphragm; The lower wall is where the anterior and posterior layers of the greater omentum fold (if the anterior and posterior layers of the greater omentum heal closely, even if there is a transverse colon, the upper edge of the anterior and posterior layers of the greater omentum and the transverse colon heal is the lower wall); The left side wall is spleen, gastric spleen ligament and spleen-kidney ligament; The right wall is not obvious, and there is a hole at the upper end that can pass through the horizontal finger size of 1-2, which is an omentum hole. On the right side of the omental sac is the omental foramen, which is the only passage between the omental sac and the large peritoneal cavity. Adult omental foramen can accommodate 1~2 fingers.