The Descending Colon (colon descendens) passes downward through the left hypochondriac and lumbar regions along the lateral border of the left kidney.
At the lower end of the kidney it turns medialward toward the lateral border of the Psoas, and then descends, in the angle between Psoas and Quadratus lumborum, to the crest of the ilium, where it ends in the iliac colon.
The peritoneum covers its anterior surface and sides, while its posterior surface is connected by areolar tissue with the lower and lateral part of the left kidney, the aponeurotic origin of the Transversus abdominis, and the Quadratus lumborum. It is smaller in caliber and more deeply placed than the ascending colon, and is more frequently covered with peritoneum on its posterior surface than the ascending colon (Treves). In front of it are some coils of small intestine.