Mesokolonit

Mesokolonit, commonly referred to in English as the mesocolon, is a peritoneal fold that attaches portions of the large intestine to the posterior abdominal wall. It forms part of the dorsal mesentery and provides a conduit for vessels, nerves, and lymphatics that supply the colon. The major mesocolons are the transverse mesocolon, which connects the transverse colon to the posterior abdominal wall near the pancreas, and the sigmoid mesocolon, which attaches the sigmoid colon to the pelvic wall. The ascending and descending segments of the colon are generally retroperitoneal and lack a true mesocolon.

Contents and function: The mesocolon contains arterial branches of the mesenteric vessels (for example, the middle colic, left colic, and sigmoid arteries), corresponding venous drainage, lymphatic channels and nodes, autonomic nerve plexuses, and adipose tissue. It serves as a pathway for blood supply and innervation while allowing a degree of mobility to the attached colon.

Development: Embryologically, the mesocolon arises from the dorsal mesentery during gut rotation and fixation, reflecting how the colon becomes anchored to the posterior abdominal wall.

Clinical significance: In colorectal surgery, removing the mesocolon with its lymphovascular supply (mesocolic excision) is an important aspect of oncologic colectomy to achieve clear margins. Defects or aberrations in the mesocolon can give rise to internal hernias. Inflammatory processes can involve the mesocolon and are sometimes described as mesocolitis, though this is not a distinct, standalone disease.

Etymology: The term derives from Greek mesos, middle, and kolon, colon.