Ischaemic colitis most frequently affects the splenic flexure. What anatomical feature explains this predilection?
- A It lies at the watershed between the superior and inferior mesenteric arterial territories ✓
- B It is the narrowest segment of the colon
- C Its venous drainage lacks valves, causing congestion
- D It receives its supply solely from the marginal artery of Drummond
Correct answer: A. It lies at the watershed between the superior and inferior mesenteric arterial territories
Explanation
The splenic flexure sits at Griffiths point, the watershed zone between the terminal branches of the middle colic artery from the superior mesenteric artery and the ascending branch of the left colic artery from the inferior mesenteric artery. Collateral flow here is poor, so any fall in colonic perfusion hits this segment first. The caecum at the junction of ileocolic and right colic branches is another watershed site. Calibre, venous anatomy and the marginal artery do not explain the distribution.
Reference: Sabiston Textbook of Surgery, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.