Anatomic CT demonstration of the peritoneal spaces, ligaments, and mesenteries: normal and pathologic processes.

Computed tomography (CT) has become increasingly useful in the detection of intraabdominal disease. Owing to the widespread use of CT, it is essential that radiologists have a thorough understanding of the peritoneal spaces and the ligaments and mesenteries that form their boundaries. The majority of ligaments and mesenteries in the abdomen are formed from remnants of the ventral and dorsal mesenteries, which suspend the primitive gut. Unlike the abdominal ligaments, the pelvic ligaments are mainly formed by reflections of peritoneum over the pelvic organs or structures. The mesenteries and ligaments form the boundaries of the peritoneal spaces; this knowledge aids in localizing fluid collections, allowing the differential diagnosis to be narrowed. The ability to localize fluid collections accurately is also important if percutaneous or surgical drainage is to be performed. In addition, neoplasms can be more accurately staged when the pathway of spread through adjacent ligaments and mesenteries is understood.