Largest hollow space of the body, between the diaphragm and the top of the pelvic cavity and surrounded by the spine and the abdominal muscles and others. It contains most of the alimentary canal, the liver and pancreas, the spleen, the kidneys, and the adrenal glands. It is lined by the peritoneum, a membrane covering the cavity's inside wall (parietal peritoneum) and each organ or structure in it (visceral peritoneum). Disorders include ascites (fluid in the peritoneal cavity) and peritonitis.
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The abdominal cavity is lined with a protective membrane termed the peritoneum. The kidneys are located in the abdominal cavity behind the peritoneum, in the retroperitoneum. The viscera are also covered, in the front, with a layer of peritoneum called the greater omentum (or omental apron).