Transverse colon !
The transverse colon is the part of the large intestine that crosses the upper belly from right to left, below the stomach.
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What it is
The part of the colon crossing the upper abdomen, hanging from the transverse mesocolon.
What it does
Moves contents from right to left.
Key facts
- Where
- From hepatic to splenic (left colic) flexure; intraperitoneal on transverse mesocolon; most mobile part of colon
- Blood supply
- Middle colic artery (SMA) for proximal two-thirds; left colic (IMA) for distal third; watershed at splenic flexure
- Nerve
- Proximal two-thirds: superior mesenteric plexus and vagus; distal third: inferior mesenteric plexus and pelvic splanchnic nerves (S2–S4)
- Function
- Absorbs water; carries contents right to left; midgut–hindgut junction at its distal third
Relations
- Above
- Greater curvature of the stomach (joined by the gastrocolic ligament), the liver and gallbladder on the right, the spleen at the splenic flexure
- In front
- Greater omentum and the anterior abdominal wall
- Behind
- Transverse mesocolon, whose root crosses D2 and the head and body of the pancreas
- Below
- Loops of jejunum and ileum in the infracolic compartment
- Lateral
- Left end: the splenic flexure, higher than the hepatic flexure and tied to the diaphragm by the phrenicocolic ligament
How to find it
Its height varies: it may sag to the umbilicus or lower when standing. At laparotomy it is lifted with the greater omentum to expose the small bowel; at colonoscopy its lumen looks triangular.
On imaging
In toxic megacolon of ulcerative colitis, a supine abdominal X-ray shows a dilated transverse colon (often more than about 6 cm), because gas rises to it. Colon placed between the liver and diaphragm (Chilaiditi sign) can mimic free air under the diaphragm.
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
- Mobilizing the splenic flexure (dividing the phrenicocolic and splenocolic attachments) risks tearing the splenic capsule
- Pain from its proximal two thirds (midgut) is felt around the umbilicus; from the distal third (hindgut), in the suprapubic region
- Gastric and pancreatic cancers can invade it through the gastrocolic ligament and transverse mesocolon
Anatomical variants
- Hepatodiaphragmatic interposition (Chilaiditi sign): a loop of colon, usually the hepatic flexure or the transverse colon, lies between the liver and the right hemidiaphragm; on a chest X-ray it can be mistaken for free air, but haustral folds show inside the gas
Development
Its proximal two thirds come from the midgut (superior mesenteric artery, vagus) and its distal third from the hindgut (inferior mesenteric artery, pelvic splanchnic nerves). The back layer of the greater omentum fuses with the transverse mesocolon, which is why the omentum appears to hang from the colon.
Related conditions
- Ulcerative colitis
- Clostridioides difficile infection
- Colorectal polyps and hereditary polyposis syndromes (FAP, Lynch)
- Paralytic ileus and colonic pseudo-obstruction (Ogilvie)
- Microscopic colitis
- Cytomegalovirus infection
- Postoperative ileus
Test yourself
Think of the answer, then tap the question to see it.
Why is the splenic flexure a classic site of ischemic colitis?
It is the watershed between middle colic (SMA) and left colic (IMA) territories, where the marginal artery can be weak (Griffiths point).
Which arteries supply the transverse colon?
The middle colic artery (SMA) for the proximal two thirds and the left colic artery (IMA) for the distal third.
Which ligament is opened to enter the lesser sac along the transverse colon?
The gastrocolic ligament, joining the greater curvature to the transverse colon; it is the usual route to the back of the stomach and the pancreas.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- colon transversum TA2 2984
- Official Spanish (DeCS)
- Colon transverso DeCS D044684
- English (TA2)
- Transverse colon
Related
Sources: Terminologia Anatomica (TA2); DeCS; Anatomy, Abdomen and Pelvis: Large Intestine; 23.5 The Small and Large Intestines (OpenStax (Rice University), 2022) · adapted, CC BY 4.0; Anatomy of the Human Body (20th ed.): The Digestive Apparatus (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain.
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Representative model, for educational purposes only.
