The Influence of the Forearm Muscles on Distal Radioulnar Joint Stability

The distal radioulnar joint (DRUJ) is crucial for the rotational movement of the forearm, as well as for power and load transfer. Little was known about the importance and relative contribution of musculoskeletal units to the stabilization of this joint. We quantified the influence of the flexor carpi ulnaris (FCU) and the extensor carpi ulnaris (ECU) muscles on DRUJ stability. Our results indicate that intentional ulnar forearm muscle activation results in 70 % less anteroposterior ulnar head translation and greater DRUJ stability.