 the peritoneum is a single continuous sheet of cirrus membrane. Throughout development organs become draped in peritoneum like so. If we cut this model in half we see two layers here. So any peritoneum that is in contact with or heading towards an abdominal organ is called visceral peritoneum. All other peritoneum will be adhered to the abdominal wall. And it's called parietal peritoneum. So to better understand these relationships we're going to bring in this model which is a simplified schematic of the abdomen. This is the abdominal wall and anteriorly that is made up of skin, muscle and fat to varying degrees. The deepest layer of the abdominal wall is this thin fluid secreting membrane known as peritoneum. It's stretched around the whole abdomen and I use the phrase stretched around because this is the literal meaning of the word peritoneum. In this schematic model everything with this coloured border is peritoneum. As we mentioned before its subcategories are visceral peritoneum that's in blue and then parietal peritoneum which is in tan. Visceral means of organs and parietal means of walls. Visceral peritoneum is adhered to abdominal organs while parietal peritoneum is adhered directly to the abdominal wall. There are some areas where the peritoneum doesn't cover the abdominal wall where an organ gets in its way. The pancreas is one example that's only partly covered in peritoneum and its posterior surface is in contact with the abdominal wall. This makes it a retroperitoneal organ. It indents into the peritoneum like so. Most abdominal viscera are completely covered in peritoneum. They achieve this by effectively growing into the peritoneum. Think back to our animation from before the organ becoming draped in peritoneum. So as they do this as they grow into the peritoneum they take part of it with them and end up completely surrounded by it like so. And the layer that surrounds them is called visceral peritoneum now and so is the peritoneum which heads out from the wall that they took with them. This being a schematic version of the liver. There are two layers extending from the liver which contribute to the visceral peritoneum of the stomach. And double layers of peritoneum connected like this to the stomach are known as omentum. The double layer attaching to the lesser curvature of the stomach is the lesser omentum. The double layer attaching to the greater curvature of the stomach is the greater omentum. And the greater omentum extends down like so. It then folds up, moves over the large bowel to become continuous with the peritoneum of the posterior abdominal wall. The mesentery is more difficult to draw and visualize but it is enough to know its origin from near the left side of the L2 vertebra to the right sacroiliac joint. And what it goes out to envelop is all of the small bowel some of the large bowel too. It's a complex fan shaped structure full of blood vessels lymphatics and nerves. Click the link in the video description to navigate around this model yourself. And good luck understanding this difficult topic in anatomy. Hit subscribe if you liked this video. Thanks for watching and we will see you next time.