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.
Horizontal plane through the kidneys, showing subdivisions of the retroperitoneal space. The anterior and posterior pararenal spaces have been exaggerated to provide representation of their relation to other retroperitoneal structures.
Human kidneys viewed from behind with spine removed
The retroperitoneum can be further subdivided into the following:
- Perirenal (or perinephric) space
- Anterior pararenal (or paranephric) space
- Posterior pararenal (or paranephric) space
Structures that lie behind the peritoneum are termed "retroperitoneal". Organs that were once suspended within the abdominal cavity by mesentery but migrated posterior to the peritoneum during the course of embryogenesis to become retroperitoneal are considered to be secondarily retroperitoneal organs.
- Primarily retroperitoneal, meaning the structures were retroperitoneal during the entirety of development:
- Secondarily retroperitoneal, meaning the structures initially were suspended in mesentery and later migrated behind the peritoneum during development
- Perirenal space
It is also called the perinephric space. Bounded by the anterior and posterior leafs of the renal fascia. It contains the following structures:
- Adrenal gland
- Renal vessels
- Perirenal fat, which is also called the "adipose capsule of the kidney", and may be regarded as being part of the renal capsule.
- Anterior pararenal space
- Posterior pararenal space
Bounded by the posterior leaf of the renal fascia and the muscles of the posterior abdominal wall. It contains only fat ("pararenal fat"), and is also called the "paranephric body", or "pararenal fat body".
- Gray's Anatomy for Students, 2nd Ed. 2010. Pg. 251
- Ryan, Stephanie; McNicholas, Michelle; Eustace, Stephen (2004). Anatomy for Diagnostic Imaging. Sydney: Saunders. p. 191. ISBN 978-0-7020-2620-1.
- Kyung Won Chung (2005). Gross Anatomy (Board Review). Hagerstown, MD: Lippincott Williams & Wilkins. p. 256. ISBN 0-7817-5309-0.
- K. L. Moore; A. F. Dalley; A. M. R. Agur (2005). Clinically Oriented Anatomy. Hagerstown, MD: Lippincott Williams & Wilkins. pp. 1209. ISBN 0-7817-3639-0.
- University of Michigan - Lab Manual - Kidneys & Retroperitoneum