Ascending mesocolon

The ascending (left) mesocolon and the descending (right) mesocolon are peritoneal folds attached respectively to ascending and descending colon.

The ascending mesocolon was previously mentioned as a no real mesentery because it is not formed by two peritoneal layers suspending the colon. The ascending and descending mesocolons were usually described as separate peritoneal folds that would have fuses with the posterior wall of abdomen in the fourth month of embryonic development

But actually it is recommended to regard the ascending and descending mesocolon as a continuation of the mesentery of the small bowel, included in the the mesenteric organ (i.e. small intestinal mesentery, right, transverse, left mesocolon, mesosigmoid and mesorectum) would be a contiguous entity from duodenal flexure to mesorectal levels.