A 68-year-old man develops sudden left-sided abdominal pain and bloody diarrhoea on the second day after emergency repair of a ruptured abdominal aortic aneurysm. Plain abdominal radiograph shows 'thumbprinting' of the colon. Which segment of the colon is most commonly affected in this condition?

• A Splenic flexure ✓
• B Caecum
• C Ascending colon
• D Rectum

Explanation

Ischaemic colitis most often affects the splenic flexure, a watershed zone (Griffiths point) between the territories of the superior and inferior mesenteric arteries, poorly collateralised and therefore vulnerable to low flow. The caecum is another watershed area but is affected less frequently. The rectum is rarely involved because it has a rich dual blood supply from the inferior mesenteric and internal iliac (middle and inferior rectal) arteries.

Reference: Sabiston Textbook of Surgery, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.