| Retroperitoneal space | |
|---|---|
 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 | |
| Details | |
| Identifiers | |
| Latin | spatium retroperitoneale |
| MeSH | D012187 |
| TA98 | A10.1.01.002 |
| TA2 | 3814 |
| FMA | 15080 |
| Anatomical terminology | |
Theretroperitoneal space (retroperitoneum) is theanatomical space (sometimes apotential space) behind (retro) theperitoneum. It has no specific delineating anatomical structures. Organs are retroperitoneal if they have peritoneum on their anterior side only. Structures that are not suspended bymesentery in the abdominal cavity and that lie between the parietal peritoneum and abdominal wall are classified as retroperitoneal.[1]
This is different from organs that are not retroperitoneal, which have peritoneum on their posterior side and are suspended by mesentery in the abdominal cavity.
The retroperitoneum can be further subdivided into the following:[2]
Structures that lie behind theperitoneum are termed "retroperitoneal". Organs that were once suspended within the abdominal cavity bymesentery but migrated posterior to the peritoneum during the course ofembryogenesis to become retroperitoneal are considered to be secondarily retroperitoneal organs.
It is also called the perinephric space. Bounded by the anterior and posterior leaves of therenal fascia. It contains the following structures:
Bounded by the posterior layer ofperitoneum and the anterior leaf of therenal fascia. It contains the following structures:
Bounded by the posterior leaf of the renal fascia and the muscles of the posterior abdominal wall. It contains only fat ("pararenal fat" also known as "pararenal fat body", "paranephric body", or "paranephric fat").
Pararenal fat is a fatty layer situated posterior to the renal compartment, and extending inferiorly into theiliac fossa.[7] It is situated posterior to the posterior aspect ofrenal fascia, and anterior to the aponeuroses of the retrorenal muscles. It is plentiful in thedihedral angle of theiliopsoas muscle and thequadratus lumborum muscle, filling the lumbar fossa posterior and inferior to the kidney.[8]
Bleeding from a blood vessel or structure in the retroperitoneal area such as theaorta orinferior vena cava into the retroperitoneal space can lead to aretroperitoneal hemorrhage.
The portion of the retroperitoneum that is posterior to the wall of the abdomen and superior to the iliac vessels is of importance ingynecologic oncology.[9] This is the region where para-aortic and paracavallymphadenectomies take place. The lateral boundary of the retroperitoneum is defined by the ascending and descending colon.[10]
It is also possible to have aneoplasm in this area, more commonly ametastasis; or very rarely a primary neoplasm. The most common type is asarcoma followed bylymphoma,extragonadal germ cell tumor, andgastrointestinal stromal tumor/GIST.[11] Examples of tumors include:
Examples of sarcomas include:
