The Allen test assesses collateral circulation in which artery?

The Allen test assesses collateral circulation in which artery?

• A. Radial
• B. Ulnar
• C. Brachial
• D. Femoral

Answer: (B)

The Allen test checks whether the hand has enough collateral blood flow through the ulnar artery via the palmar arches to maintain perfusion if the other major artery is blocked. If color returns quickly when the ulnar pathway is tested (with the radial artery occluded), it shows the ulnar artery can adequately supply the hand, indicating good collateral circulation. If color does not return promptly, the hand may depend mainly on the radial artery, meaning collateral flow is insufficient. So the artery being evaluated for this collateral route is the ulnar artery.

The Allen test checks whether the hand has enough collateral blood flow through the ulnar artery via the palmar arches to maintain perfusion if the other major artery is blocked. If color returns quickly when the ulnar pathway is tested (with the radial artery occluded), it shows the ulnar artery can adequately supply the hand, indicating good collateral circulation. If color does not return promptly, the hand may depend mainly on the radial artery, meaning collateral flow is insufficient. So the artery being evaluated for this collateral route is the ulnar artery.