Mesenteric

Mesenteric refers to the mesentery, a double layer of peritoneum that attaches the intestines to the posterior abdominal wall. It provides support and a conduit for vessels, nerves, and lymphatics that supply the gastrointestinal tract. The term is used for structures related to these peritoneal folds and their associated tissues.

Anatomy and organization: The mesentery proper is a fan-shaped sheet attaching the small intestine to the posterior abdominal wall, with a mesenteric root approximately 15–20 cm long. It contains fat, blood vessels, lymphatics, and nerves that travel to and from the intestinal wall. The mesentery is continuous with the dorsal abdominal wall and varies in length and fat content with age and body habitus.

Vascular supply and drainage: The superior mesenteric artery supplies the majority of the small intestine and parts of the proximal large intestine; its branches extend through the mesentery to the intestinal wall. The inferior mesenteric artery supplies the distal large intestine. Venous drainage runs through the superior and inferior mesenteric veins, which empty into the portal venous system, often via the splenic vein joining the superior mesenteric vein.

Function and clinical relevance: The mesentery stabilizes the intestines while allowing sufficient mobility for peristalsis and houses essential vessels, nerves, and lymphatics. Clinically important conditions include mesenteric ischemia (acute or chronic), mesenteric panniculitis (inflammation of the mesenteric fat), and mesenteric edema or cystic formations. Mesenteric lymphadenitis can mimic appendicitis and is relevant in differential diagnoses.

Embryology and terminology: The mesentery derives from the dorsal and ventral peritoneal folds formed during embryonic development; parts may become retroperitoneal as development progresses. The word derives from Greek mesos (middle) and enteron (intestine).