Peritonealraum

Peritonealraum, known in English as the peritoneal cavity, is a potential space within the abdomen and part of the abdominopelvic cavity. It is lined on both sides by serous Peritoneum, consisting of parietal peritoneum lining the abdominal walls and visceral peritoneum covering the abdominal organs. The cavity contains a small amount of lubricating peritoneal fluid that reduces friction during organ movement.

Anatomically, the peritoneal cavity extends from the diaphragm to the pelvic floor and is divided into the greater sac and the lesser sac (omental bursa). The greater sac is the main and largest compartment, whereas the lesser sac lies posterior to the stomach and liver, communicating with the greater sac via the epiploic foramen. The peritoneum forms a series of reflections, including mesenteries, ligaments, and omenta, which suspend and secure intraperitoneal organs. Organs are classified as intraperitoneal (mainly suspended by mesenteries) or retroperitoneal (situated outside the peritoneal cavity).

Functions of the peritoneal cavity include facilitating smooth movement of viscera, supporting immune defense, and providing a pathway for blood and lymphatic drainage within the peritoneal reflections. The cavity is clinically significant in conditions such as ascites (accumulation of fluid), peritonitis (inflammation of the peritoneum), and disorders treated by peritoneal dialysis. Developmentally, the peritoneal cavity arises from the intraembryonic coelom and remains lined by mesothelium throughout life.