<prompt> Muscle in extension compament of forearm which causes flexion of elbowBrachioradialisAbductor pollicis longusExtensor pollicis longusExtensor caipi radialis longus  <response>: Brachioradialis - flexes forearm at elbow joint; rotates forearm to the mid prone position from supine or prone positions. Ref : B D Chaurasias Human Anatomy , seventh edition , volume 1 , pg. no., 138 