Retroperitoneal describes structures located where?

• A. In Front of the Peritoneum
• B. Behind the Peritoneum of the Abdominal Cavity
• C. Within the Intestinal Lumen
• D. On the Surface of the Liver

Answer: (B)

Retroperitoneal means located behind the lining of the abdominal cavity called the peritoneum. The peritoneum forms a sac that lines the cavity and covers many organs; retroperitoneal structures lie posterior to that lining, often only partially covered by peritoneum. This explains why they’re it’s not inside the peritoneal cavity like intraperitoneal organs (stomach, liver, most of the small intestine), and it’s also why major vessels run in front of them in the posterior abdominal wall. Examples include the kidneys, adrenal glands, aorta, and inferior vena cava, as well as parts of the duodenum and pancreas. The intestinal lumen itself is the hollow inside the gut tube, not behind the peritoneum, and the liver’s surface is largely intraperitoneal.