peritoneum (pĕrətənē´əm), multilayered membrane which lines the abdominal cavity, and supports and covers the organs within it. The part of the membrane that lines the abdominal cavity is called the parietal peritoneum. The portion that covers the internal organs, or viscera, is known as the visceral peritoneum and forms the outer layer (serosa) of most of the intestinal tract. The supportive peritoneum forms sheets of greatly modified membranes called mesenteries. These tissues hold the organs of the digestive tract in position and convey nerves, blood vessels, and lymphatic ducts to the viscera. The space between the visceral and parietal membranes contains a watery fluid that permits the abdominal organs to slide freely against the abdominal wall. A ruptured appendix can lead to inflammation of the peritoneum, a condition known as peritonitis.

peritoneum A membrane which lines the inside of the abdomen and covers its contents. The peritoneal ‘cavity’ is an enclosed sac between the lining and the contents, and normally contains only sufficient fluid to lubricate the movement of the loops of the intestines, allowing them to slide freely over each other and against the inside of the abdominal wall. Disease of the stomach, intestines, or appendix which causes leakage or rupture (perforation) can result in dissemination of infected material throughout the cavity, causing peritonitis. Accumulation of fluid in the peritoneal cavity (ascites) occurs along with generalized oedema in conditions such as heart failure or kidney failure.

Stuart Judge

per·i·to·ne·um / ˌperitnˈēəm/ • n. (pl. -ne·ums or -ne·a / -ˈnēə/ ) Anat. the serous membrane lining the cavity of the abdomen and covering the abdominal organs. DERIVATIVES: per·i·to·ne·al / -ˈēəl/ adj.

peritoneum (pe-ri-tŏn-ee-ŭm) n. the serous membrane of the abdominal cavity (see illustration). parietal p. the part of the peritoneum that lines the walls of the abdomen. visceral p. the part of the peritoneum that covers the abdominal organs. See also mesentery, omentum.
—peritoneal adj.

peritoneum XVI. — late L. peritonæum, -ēum — Gr. peritónaion, -eion, sb. use of n. of peritónaios, f. peritonos stretched around, f. PERI- + -tonos stretched.

peritoneum The thin layer of tissue (see serous membrane) that lines the abdominal cavity of vertebrates and covers the abdominal organs. See also mesentery.

peritoneum Strong membrane of connective tissue that lines the body's abdominal wall and covers the abdominal organs. See also peritonitis

peritoneum See MESENTERY.

peritoneum •um •Graeme, graham •athenaeum, atheneum, coliseum, Liam, lyceum, mausoleum, museum, peritoneum, propylaeum, Te Deum •Rijksmuseum