Q.What are Retroperitoneal organs?

Retroperitoneal Organs

The organs inside your abdomen are not just floating loose — they are arranged in relation to a thin membrane called the peritoneum that lines the abdominal cavity. Where an organ sits relative to this membrane turns out to be a useful and frequently asked anatomical detail, and it gives us the term retroperitoneal.

The peritoneum, briefly

The peritoneum is a smooth membrane lining the abdominal cavity and covering many of the organs within it. Most abdominal organs (like much of the intestine) hang within the peritoneal cavity, suspended by folds of this membrane. But some organs lie behind it.

What "retroperitoneal" means

Retro means "behind." A retroperitoneal organ is one that lies behind the peritoneum, against the dorsal (back) body wall of the abdomen, rather than being suspended freely inside the peritoneal cavity. In other words, only their front surface is covered by peritoneum; their back rests directly against the posterior wall.

The main retroperitoneal organs

The organs usually described as retroperitoneal include:

• Kidneys — pressed against the back wall of the abdomen on either side of the vertebral column; their retroperitoneal position is the most commonly cited example.
• Pancreas — much of it lies behind the peritoneum.
• Parts of the gut — certain portions of the intestine (and some other structures such as parts of the urinary tract) are also retroperitoneal.

Why the position matters …