Peritoneal anatomy

•. 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 and 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 infective, 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. •. CT and, to a lesser extent, MRI allow us to accurately examine the complex anatomy of the peritoneal cavity, which is the key to understanding the pathological processes affecting it.