[Subperitoneal space and pathways of abdominal and pelvic tumor spread from the perspective of imaging].

The abdomen and pelvis have been divided anatomically and clinically into peritoneal cavity and subperitoneal space by peritoneum. The subserosal areolar tissue which lines the inner surfaces of the peritoneum and the musculature of the abdomen and pelvis form the subperitoneal space. The surfaces of organs are covered by peritoneum, therefore, organs are located within subperitoneal space. Those organs that are deep to the posterior peritoneum are called extraperitoneal. Peritoneal reflections comprise the abdominal major ligaments and mesenteries. They contain the branches of the vascular, lymphatic, and nervous systems within subperitoneal space to supply the corresponding organs. Either the relationships of typical location and organ or the landmarks provided by major constituent vessels give a help to recognize ligaments and mesenteries on computed tomographic scans. The abdomen and pelvis may be visualized as unifying, anatomically continuous potential space by ligaments and mesenteries, which provide continuity of anatomic planes and permit the spread of diseases between intraperitoneal compartments, between extraperitoneal spaces, and between intraperitoneal and extraperitoneal localized sites. Understanding the anatomy of subperitoneal space would increase the capabilities to detect pathways of spread and localizing features of infections, malignancies, and traumas.