L17 Peritoneum PDF

L17: PERITONEUM PERITONEUM is a covering of organ Large serous membrane lining the abdominal cavity Divided into: a. An outer or parietal layer b. An inner or visceral layer Parietal Peritoneum: - lines the inner surface of the abdominal and pelvic walls and the lower surface of the diaphragm. - Der...

L17: PERITONEUM PERITONEUM is a covering of organ Large serous membrane lining the abdominal cavity Divided into: a. An outer or parietal layer b. An inner or visceral layer Parietal Peritoneum: - lines the inner surface of the abdominal and pelvic walls and the lower surface of the diaphragm. - Derived from the somatopleuric layer of the lateral plate mesoderm - Its blood supply and nerve supply are the same as those of the overlying body wall. Visceral Peritoneum: - It lines the outer surface of the viscera - derived from the splanchnopleuric layer - blood supply and nerve supply are the same as those of the underlying viscera PERITONEAL CAVITY : cavity between the parietal and visceral layers - The cavity is filled with a small amount of serous peritoneal fluid - Peritoneal fluid enables the peritoneal layers to slide against each other with little friction DIVISIONS There are two divisions of the peritoneal cavity: Lesser sac (omental bursa) and greater sac. LESSER SAC (OMENTAL BURSA): Behind ( posterior to ) the stomach and liver In front ( anterior to ) pancreas and duodenum - Provides space for unhindered movement of the stomach. ( because the stomach will expand ) - Irregular shape with one superior and one inferior recess. - The superior recess is bordered by the diaphragm (between the thorax and abdomen) GREATER SAC greater sac extends from the diaphragm to the pelvic cavity. It is divided into the supracolic and infracolic compartments by the transverse mesocolon. The supracolic compartment is found anterior and superior to the transverse mesocolon, and contains the liver, stomach and spleen. The infracolic compartment is posterior and inferior to the transverse mesocolon ( the intestine) epiploic foramen: The lesser sac communicates with the greater sac via the epiploic foramen Borders of the epiploic Foramen : Anterior – hepatoduodenal ligament Posterior – inferior vena cava and the right crus of the diaphragm Superior – caudate lobe of the liver Inferior – superior part of the duodenum The mesentery is the folds of peritoneum that suspend organs from the posterior abdominal wall. ( seen in the intestine) The projection of an organ into the peritoneum creates a peritoneal fold which extends from the abdominal wall, wraps around that organ, and extends back to the abdominal wall. These double layers of peritoneum are the mesentery The mesentery of the small intestine is simply called the mesentery, other parts of the digestive system have their mesenteries named transverse mesocolon: mesentery of large intestine transverse mesocolon sigmoid mesocolon : mesentery of sigmoid mesoappendix: mesentery of appendix OMENTUM = in the stomach The omenta are two layers of peritoneum which have fused, and extend from the stomach and duodenum to neighboring organs. The greater omentum hangs like a curtain covering the anterior surface of the small intestine. It hangs from the proximal duodenum and greater curvature of the stomach and then folds to attach superiorly to the anterior surface of the transverse colon and its mesentery on the inferior edge. The lesser omentum extends superiorly from the lesser curvature of the stomach and proximal duodenum to the liver. Lesser omentum on top and greater omentum below Greater omentum starts from greater curvature of the stomach , continues to duodenum, from there it’s going down to transverse colon, then goes more down to reach the small intestine. Lesser omentum coming from lesser curvature, going upwards superiorly to the liver PERITONEAL LIGAMENTS They have two main functions: To attach organs to the abdominal wall and/or to other abdominal organs and hold them in position To carry neurovascular structures which supply abdominal organs Splenic ligaments: Phrenicocolic ligament (sustentaculum lienis) Gastrosplenic ligament Splenorenal (lienorenal) ligament Gastric ligaments: Gastrophrenic ligament Gastrocolic ligament Hepatic ligaments: Falciform ligament Gastrohepatic ligament Hepatoduodenal ligament PERITONEAL RELATIONS - Intraperitoneal organs are completely wrapped by visceral peritoneum : they are the spleen , stomach , superior part of the duodenum, transverse colon … - Retroperitoneal organs are found posterior to the peritoneum in the retroperitoneal space with only their anterior wall is covered by the parietal peritoneum: they are the kidney , glands , ureter… Ascites: Ascites by definition is accumulation of more than 20 milliliters of fluid within the peritoneal cavity. Peritonitis: Peritonitis is an inflammation of the peritoneum