Abdominal Cavity and Peritoneum MCQs

Due to gut rotation and mesentery fusions, most of the pancreas and duodenum and the ascending and descending colons become secondarily retroperitoneal. Reference - Textbook of Langman's, 12th Edition, Digestive System Embryology Page number - 208

Fusion fascia forms when an organ becomes secondarily retroperitoneal. Secondarily retroperitoneal organs started out in a mesentery, but then got pushed against the posterior body wall during development. So, the peritoneal covering on the face of these organs which was pushed against the posterior body wall became fusion fascia--a relatively avascular plane of fascia that holds these organs to the posterior body wall. The ascending colon, descending colon, duodenum, and pancreas are all secondarily retroperitoneal organs which are attached by fusion fascia. The kidney is an entirely retroperitoneal organ that was never associated with a mesentery during development. So, it is not attached to the body wall by fusion fascia. Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Abdomen, Page number - 186

The ascending colon is on the right side of the abdomen--the surgeon would not need to explore the left lower quadrant! Because the ascending colon is supplied by the superior mesenteric artery, the surgeon might need to ligate branches of this artery, and the surgeon would also want to check the superior mesenteric nodes for metastasis. Since the ascending colon is secondarily retroperitoneal, it can be mobilized by freeing its fusion fascia. Finally, it's always a good idea to protect the peritoneum from fecal contamination! Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Abdomen, Page number - 164

The descending colon drains into the inferior mesenteric nodes--these are the lymph nodes that the surgeon would want to check for enlargement, not the sacral nodes. The descending colon can be approached from the lower left quadrant. It is a secondarily retroperitoneal organ, so it can be mobilized by freeing fusion fascia. It would also be important to ligate branches of the left colic artery, since this is the branch of the inferior mesenteric that supplies the descending colon. And, obviously, the peritoneum should be protected from fecal contamination! Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Abdomen, Page number - 143

The omental apron is the portion of the greater omentum, continuous with gastrocolic ligament, which hangs from the transverse colon. Early in development, it is an open sac, communicating with the lesser sac or omental bursa. The walls of the sac are two layers of peritoneum, forming a quadruple layer when the bag fuses. Reference - Textbook of Langman's, 12th Edition, Digestive System Embryology Page number - 208

The hepatic branch of the anterior vagal trunk travels in the upper portion of the hepatogastric ligament. The posterior vagal trunk supplies a celiac branch deep to the hepatogastric ligament. The greater thoracic splanchnic branches to the suprarenal glands come off the greater thoracic splanchnic nerves as they pass through the diaphragm. Then, the greater thoracic splanchnic nerves continue on to synapse in the celiac ganglia. Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Abdomen, Page number - 158

The gastrosplenic ligament is a derivative of the dorsal mesentery. Mesenteries are double layers of the peritoneum that enclose an organ and connect it to the body wall. They provide pathways for vessels, nerves, and lymphatics to and from the abdominal viscera. Reference - Textbook of Langman's, 12th Edition, Digestive System Embryology Page number - 208

The entire posterior surface of the pancreas is devoid of the peritoneum. The posterior surface of the pancreas lies over the fascia of Toldt in front of the aorta. The splenic vein traverses directly on this surface. Only parts of the uncinate process (where the superior mesenteric vessels descend on it) are also devoid of the peritoneum. The entire anterior surface of the body is covered by peritoneum and the tail lies between the layers of the splenorenal ligament, which is formed from the peritoneum. Note that the pancreas is a retroperitoneal organ (except for the tail), in that it is not enveloped with the peritoneum but the anterior surface is in contact with the peritoneum. Reference: Textbook of Gray's Anatomy for students, 3rd Edition, Abdomen, Page number - 176