A 68-year-old woman with atrial fibrillation develops sudden left-sided abdominal pain and bloody diarrhoea after an episode of hypotension. CT shows thickening of the bowel wall at the splenic flexure without perforation. Which anatomical feature explains the location of this injury?

• A Its venous drainage lacks collateral connections
• B It has the longest vasa recta of any colonic segment
• C It receives dual arterial supply from the SMA and IMA
• D It lies at the junction of midgut and hindgut blood supply, a watershed zone ✓

Explanation

The splenic flexure sits at Griffiths point, the watershed between the terminal branches of the superior mesenteric artery and the inferior mesenteric artery, making it the commonest site of ischaemic colitis. The rectosigmoid junction at Sudeck point is the second watershed area. Dual supply does not protect this segment because the marginal artery here is often poorly developed, and venous anatomy is irrelevant to the arterial watershed mechanism.

Reference: Sabiston Textbook of Surgery, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.