Fig. 1From: The Allen’s test: revisiting the importance of bidirectional testing to determine candidacy and design of radial forearm free flap harvest in the era of trans radial endovascular access proceduresThe ‘reverse’ Allen’s test. a. The pallor associated with occlusion of both radial and ulnar artery inflow to the hand. b. Rapid return of redness to the hand following release of radial artery pressure confirming flow through the radial arteryBack to article page