Anatomy and Physiology of Children and Adolescents - M. R. Sapin 2007

The Doctrine of Viscera (Splanchnology)
Digestive System
Peritoneum and Peritoneal Cavity

The Peritoneum and the peritoneal cavity enclosed by it are located within the Abdominal cavity. The walls of the abdominal cavity are formed by the Diaphragm superiorly, THE Vertebral Column and associated Muscles posteriorly, the anterior and lateral abdominal walls anteriorly and laterally, and the pelvic bones and muscles inferiorly. The inner surface of the abdominal cavity is lined with the endoabdominal fascia, which also contributes to The formation of the abdominal walls.

The peritoneal cavity is a narrow slit-like space enclosed by the peritoneum that partially or completely covers the Internal Organs located within the ABDOMINAL CAVITY AND the abdominal walls.

The peritoneum is a thin, durable serous membrane composed of a Connective Tissue layer whose peritoneal surface is lined with flat epithelial Cells known as mesothelium. It is subdivided into the parietal peritoneum, which lines the inner surface of the abdominal walls, and the visceral peritoneum, which covers The Stomach, Liver, Spleen, most of the Small Intestine, and other organs. The total surface area of the peritoneum in an adult is approximately 1.7 m². The peritoneal cavity contains a small amount of serous fluid. Exuded from Blood capillaries into the peritoneal cavity, this fluid moistens the peritoneum and facilitates the smooth sliding of its layers against one another during peristalsis of the stomach and intestines, as well as changes in body position. In males, the peritoneal cavity is a completely closed sac, whereas in females it communicates with the external environment via the uterine tubes and the uterine cavity. Between the inner aspect of the parietal peritoneum and the outer endoabdominal fascia, There is a varying amount of adipose tissue in certain areas.

The visceral layer of the peritoneum completely covers several internal organs from all sides: the stomach, the mesenteric part of the small intestine, the cecum, the transverse colon, the sigmoid colon, the liver, the spleen, the Uterus, and the uterine tubes. Such organs are referred to as intraperitoneal organs, meaning they are covered by the peritoneum on all sides. Other organs are covered only partially, on three sides; these are termed mesoperitoneal organs. Organs located outside the peritoneum, posterior to its parietal layer, are called extraperitoneal (retroperitoneal) organs. If an intraperitoneal organ is connected to the abdominal wall (parietal peritoneum) by a double fold of peritoneum, this fold is designated as a mesentery (e.g., the mesentery of the small intestine, the transverse mesentery). Two peritoneal folds extending from the porta hepatis to the lesser curvature of the stomach and the duodenum are known as the lesser omentum, while the folds hanging down from the greater curvature of the stomach and anteriorly covering the loops of the small intestine form the greater omentum.

Due to the complex anatomical relationships between the peritoneum and the internal organs, several recesses or compartments, known as peritoneal sacs, are formed within the peritoneal cavity. These include the hepatic bursa (containing the liver), the pregastric bursa (anterior to the stomach), and the omental bursa (posterior to the stomach). In addition, there are the right and left mesenteric sinuses (located on either side of the ROOT of the mesentery of the small intestine) and the lateral channels (situated lateral to the ascending and descending colons).