During a left hemicolectomy for cancer, the inferior mesenteric artery (IMA) is ligated at its origin. Which anatomical structure provides the primary collateral blood supply to the proximal descending colon via the marginal artery?
- A Left colic artery (branch of IMA)
- B Middle colic artery (branch of SMA) ✓
- C Superior rectal artery
- D Ileocolic artery
Correct answer: B. Middle colic artery (branch of SMA)
Explanation
The marginal artery of Drummond connects the superior mesenteric artery (SMA) and inferior mesenteric artery (IMA) territories along the mesenteric border of the colon. When the IMA is ligated high, the descending colon is perfused retrograde via the marginal artery from the middle colic artery (a branch of the SMA) through the arc of Riolan. The left colic artery is a branch of the IMA and would be sacrificed.
Reference: Gray's Anatomy for Students, 4th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.