A 68-year-old man comes to the clinic because of progressive right buttock and thigh pain when walking uphill for the past two monhts. He has hypertension, hyperlipidemia, type 2 diabetes mellitus, and a 50-pack-year smoking history. On physical examination, femoral pulse is diminished on the right, but distal pulses are faintly palpable. CT angiography shows chronic severe stenosis of the right external iliac artery proximal to the inguinal ligament, with enlarged collateral vessels around the posterior hip.
Blood flow from the internal iliac system to the deep femoral system is most likely maintained through an anastomosis involving which of the following arteries?
The correct answer is:
A) Inferior gluteal artery
The inferior gluteal artery is a branch of the internal iliac artery that participates in the cruciate anastomosis around the posterior hip. This anastomosis connects the inferior gluteal artery with the medial circumflex femoral artery, lateral circumflex femoral artery, and first perforating branch of the deep femoral artery. In chronic external iliac or proximal femoral arterial stenosis, gradual enlargement of these collateral vessels can partially maintain perfusion to the thigh. The key clue is collateral flow between the internal iliac system and the deep femoral system around the posterior hip.
Answer choice B: Inferior mesenteric artery, is incorrect. The inferior mesenteric artery supplies hindgut structures and participates in intestinal collateral circulation through the marginal artery. It does not connect the internal iliac artery to the deep femoral artery around the hip.
Answer choice C: Lateral sacral artery, is incorrect. The lateral sacral arteries arise from the internal iliac artery and supply the sacral canal, meninges, and posterior pelvic wall. Although they are internal iliac branches, they do not form the major collateral pathway to the deep femoral system.
Answer choice D: Obturator artery, is incorrect. The obturator artery is usually a branch of the internal iliac artery and enters the medial thigh through the obturator canal. It can have clinically important pelvic and thigh anastomoses, but it is not the principal internal iliac branch of the cruciate anastomosis that connects to the deep femoral system around the posterior hip.
Answer choice E: Superior gluteal artery, is incorrect. The superior gluteal artery is an internal iliac branch that exits the pelvis superior to the piriformis and participates in the trochanteric anastomosis near the femoral head. It is more closely associated with collateral supply to the femoral head than with the cruciate anastomosis connecting the internal iliac system to the deep femoral artery.
Key Learning Point
The inferior gluteal artery contributes to the cruciate anastomosis, which can provide collateral flow from the internal iliac system to the deep femoral system during chronic external iliac or proximal femoral artery stenosis.
