[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Abdomen](https://durgical.com/en/anatomy/region/abdomen/) › Descending colon [Digestive system](https://durgical.com/en/anatomy/system/digestive-system/) · [Abdomen](https://durgical.com/en/anatomy/region/abdomen/) # Descending colon The descending colon is the part of the large intestine that runs down the left side of the belly, carrying formed stool toward the [sigmoid colon](https://durgical.com/en/anatomy/sigmoid-colon/). [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=abdomen&select=descending_colon&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The part of the colon running down the left side. ## What it does Stores and moves stool down toward the sigmoid. ## Key points - Secondarily retroperitoneal; mobilized in a left colectomy by incising the white line of Toldt in the left paracolic gutter - Narrower than the right colon with formed stool, so left-sided cancers tend to obstruct and change bowel habit, while right-sided ones bleed silently - The left ureter and gonadal vessels lie behind its fusion plane and must be identified in left colon surgery ## Key facts **Where** Left flank, from splenic flexure to pelvic brim; secondarily retroperitoneal **Blood supply** Left colic artery (IMA); marginal artery **Nerve** Inferior mesenteric plexus (sympathetic, lumbar splanchnic L1–L2); pelvic [splanchnic nerves](https://durgical.com/en/anatomy/greater-thoracic-splanchnic-nerve/) (S2–S4) **Function** Stores and propels stool toward sigmoid; absorbs water ## Relations **Behind** Lateral border of the left [kidney](https://durgical.com/en/anatomy/kidney/), [quadratus lumborum](https://durgical.com/en/anatomy/quadratus-lumborum-muscle/), [iliacus](https://durgical.com/en/anatomy/iliacus-muscle/) and psoas, with the iliohypogastric, ilioinguinal and lateral femoral cutaneous nerves **Lateral** Left paracolic gutter, closed above by the phrenicocolic ligament **Medial** Loops of [jejunum](https://durgical.com/en/anatomy/jejunum/); deeper, the inferior mesenteric vein, the left [ureter](https://durgical.com/en/anatomy/ureter/) and the gonadal vessels **In front** Loops of small intestine and the [greater omentum](https://durgical.com/en/anatomy/greater-omentum/); in thin people, the anterior abdominal wall **Above** Splenic flexure, below the [spleen](https://durgical.com/en/anatomy/spleen/) and the tail of the [pancreas](https://durgical.com/en/anatomy/pancreas/) ## How to find it It projects onto the left flank. Hard stool can sometimes be felt in it as a mass that can be indented, unlike a tumor. At colonoscopy it is a fairly straight segment between the splenic flexure and the sigmoid. ## On imaging In ischemic colitis near the splenic flexure, X-ray or CT shows wall thickening and «thumbprinting» from submucosal edema. In long-standing ulcerative colitis, barium enema shows a featureless lead-pipe colon without haustra. ## Common problems - Colon polyps and colorectal cancer: screening finds them early. - Diverticular disease and diverticulitis (usually sigmoid). - Ulcerative colitis and Crohn disease. ## How it is diagnosed Colonoscopy; CT; stool tests for screening. ## Treatment - Polyps removed during colonoscopy; surgery (colectomy) for cancer or complicated disease. ## Clinical notes - Ischemic colitis favors the watershed near the splenic flexure (Griffiths point), for example after low blood flow or aortic surgery that sacrifices the [inferior mesenteric artery](https://durgical.com/en/anatomy/inferior-mesenteric-artery/) - The phrenicocolic ligament stops fluid in the left paracolic gutter from reaching the area around the spleen, so it drains toward the [pelvis](https://durgical.com/en/anatomy/region/pelvis/) - Pain from the descending colon (hindgut) is felt in the suprapubic region ## Development A hindgut derivative supplied by the inferior mesenteric artery. Its mesentery fuses with the back wall in most people, leaving the bloodless plane opened in a left colectomy; in a minority part of a descending [mesocolon](https://durgical.com/en/anatomy/mesocolon/) remains and the segment is more mobile. ## Related conditions - [Diverticular disease and diverticulitis](https://durgical.com/en/conditions/diverticular-disease-and-diverticulitis/) - [Large bowel obstruction](https://durgical.com/en/conditions/large-bowel-obstruction/) - [Ulcerative colitis](https://durgical.com/en/conditions/ulcerative-colitis/) - [Irritable bowel syndrome](https://durgical.com/en/conditions/irritable-bowel-syndrome/) - [Lower gastrointestinal bleeding](https://durgical.com/en/conditions/lower-gastrointestinal-bleeding/) - [Clostridioides difficile infection](https://durgical.com/en/conditions/clostridioides-difficile-infection/) - [Ischaemic colitis](https://durgical.com/en/conditions/ischaemic-colitis/) - [Hemolytic uremic syndrome (HUS)](https://durgical.com/en/conditions/hemolytic-uremic-syndrome/) ## Test yourself Think of the answer, then tap the question to see it. ## Why do cancers of the descending colon tend to obstruct while right-sided ones bleed silently? The left colon is narrower and carries formed stool, so tumors obstruct and change bowel habit. ## Which structures lie behind the fusion plane of the descending colon in a left colectomy? The left ureter and the gonadal vessels, which must be identified. ## Which artery supplies the descending colon? The left colic artery from the inferior mesenteric artery, plus the marginal artery. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/anatomy/descending-colon/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** colon descendens TA2 2986 **Official Spanish (DeCS)** Colon descendente DeCS D044683 **English (TA2)** Descending colon **Also called** left colon ## Related - [Transverse colon](https://durgical.com/en/anatomy/transverse-colon/) - [Sigmoid colon](https://durgical.com/en/anatomy/sigmoid-colon/) - [Colic arteries](https://durgical.com/en/anatomy/right-colic-artery/) - [Inferior mesenteric artery](https://durgical.com/en/anatomy/inferior-mesenteric-artery/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=37756&filter=ths_termall&q=Colon%20Descendente); [Anatomy, Abdomen and Pelvis: Large Intestine](https://www.ncbi.nlm.nih.gov/books/NBK470577/); [23.5 The Small and Large Intestines](https://openstax.org/books/anatomy-and-physiology-2e/pages/23-5-the-small-and-large-intestines) (OpenStax (Rice University), 2022) · adapted, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/); Anatomy of the Human Body (20th ed.): The Digestive Apparatus (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain. ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/descending-colon/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/descending-colon/