mesenteries

Mesenteries are folds of peritoneum that suspend portions of the gastrointestinal tract from the posterior abdominal wall. They enclose the intestines within a continuous sheet of peritoneum, support their movement, and provide a conduit for blood vessels, nerves, and lymphatics. The term derives from Greek meson “middle” and enteron “intestine.”

Anatomy: In the adult human, the small intestine is suspended by the mesentery proper, a fan-shaped dorsal peritoneal fold attaching along a broad mesenteric root to the posterior abdominal wall; the root measures about 15–20 cm in length. The large intestine has its own peritoneal attachments: the transverse mesocolon and sigmoid mesocolon. Ventral and dorsal mesenteries are embryological concepts, with foregut structures carrying ventral mesenteries such as the falciform ligament and lesser omentum; the dorsal mesentery gives rise to the mesentery of the midgut and hindgut.

Development: The intestines arise from a dorsal and ventral mesentery during embryogenesis; rotation and fixation transform these into the mature attachments. Recent research describes the mesentery as a single continuous organ rather than a set of discrete folds.

Function: The mesentery anchors the viscera, provides mechanical stability, and houses neurovascular structures and lymphatics within the mesenteric vessels and nodes. It also allows for growth and movement of the intestines while maintaining vascular and nervous supply.

Clinical relevance: Mesenteric defects can lead to internal hernias; mesenteric ischemia involves loss of blood supply via the mesenteric vessels; surgical procedures often involve mobilization or resection of mesenteric tissue; inflammation or panniculitis can affect mesenteric fat.