The
retroperitoneal space (
retroperitoneum) is the
anatomical space (sometimes a
potential space) in the
abdominal cavity behind (
retro) the
peritoneum. It has no specific delineating anatomical structures. Organs are retroperitoneal if they have peritoneum on their anterior side only. Structures that are not suspended by
mesentery in the abdominal cavity and that lie between the parietal peritoneum and abdominal wall are classified as retroperitoneal.