What are retroperitoneal organs

The Retroperitoneal space or just that Retroperitoneum (Retroperitoneal space) includes those anatomical structures that lie behind the peritoneum and are not enclosed by the peritoneum. "Retroperitoneal" means "behind the peritoneum".

A distinction is made in terms of evolutionary history primarily retroperitoneal and secondary retroperitonealOrgans. Those organs that arise behind the abdominal cavity are primarily retroperitoneal. These include the kidneys, adrenal glands, and ureters. In contrast to this, the secondary retroperitoneal organs arise in the abdominal cavity: They are initially intraperitoneal, and through growth (compressive and tensile forces) these organs are then pressed against the abdominal wall, whereby their shell, the visceral peritoneum, grows together with the parietal peritoneum of the abdominal wall. They therefore no longer have a mesentery and are severely restricted in their mobility compared to the organs located intraperitoneally. The secondary retroperitoneal organs in humans include:

  • Pancreas
  • Duodenum (exception: upper part, pars superior)
  • Ascending colon
  • Descending colon
  • Rectum to sacral flexure

In domestic animals, these organs, with the exception of parts of the pancreas, are intraperitoneal, so they have a mesentery.

In addition to the retroperitoneal organs, the median plane of the retroperitoneal space also contains the large axial ducts: