The peritoneum, mesenteries and omenta: normal anatomy and pathological processes

The peritoneum is the largest and most complexly arranged serous membrane in the body. The potential peritoneal spaces, the peritoneal reflections forming peritoneal ligaments, mesenteries, omenta and the natural flow of peritoneal fluid determine the route of spread of intraperitoneal fluid and, consequently, disease processes within the abdominal cavity. The peritoneal ligaments, mesenteries and omenta also serve as boundaries for disease processes and conduits for disease spread. The peritoneal cavity and its reflections are frequently involved by infectious, inflammatory, neoplastic and traumatic processes. Before the introduction of cross-sectional imaging, the peritoneum and its reflections could only be imaged with difficulty, often requiring invasive techniques. Computed tomography and, to a lesser extent, sonography and MR imaging allow the accurate examination of the complex anatomy of the peritoneal cavity, which is the key to understanding the pathological processes affecting it. This article reviews the normal peritoneal anatomy and its disease processes.