It is continuous with the two posterior layers of the greater omentum, which, after separating to surround the transverse colon, join behind it, and are continued backward to the vertebral column, where they diverge in front of the anterior border of the pancreas. This fold contains between its layers the vessels which supply the transverse colon.
The root of the transverse mesocolon extends across the anterior infra-ampullary segment of the descending duodenum (2nd part), the head of the pancreas and continues along the lower edge of the body and tail of the pancreas, and divides the peritoneal cavity into the supracolic and infracolic spaces.
Transverse mesocolon is a derivative of dorsal mesentery in the embryo and contains:
- transverse colon (in the free margin)
- middle colic vessels and their branches
- lymphatics and lymph nodes
- autonomic nerve fibers
- extraperitoneal fatty tissue