OBJECTIVE: The purpose of this study was to compare the reduction of shoulder subluxation radiologically using two types of extension arm sling. METHOD: Fifteen patients with a hemiplegic shoulder subluxation were studied. Two types of extension sling (forearm cuff type and humeral cuff type) were applied for the shoulder subluxation. On the shoulder X-ray, three parameters were measured: vertical distance (VD), horizontal distance (HD), and joint distance (JD). RESULTS: The mean values of the VD, HD, and JD of hemiplegic shoulder without a sling were 2.00+/-0.69 cm, 2.69+/-0.45 cm, and 1.53+/-0.56 cm, respectively, which were reduced to 1.00+/-0.43 cm, 2.61+/-0.46 cm, and 0.80+/-0.37cm by a forearm cuff type and to 1.80+/-0.83 cm, 2.60+/-0.45 cm, and 1.33+/-0.66 cm by a humeral cuff type. A forearm cuff type showed corrective effect in VD and JD, but a humeral cuff type did not in any of three parameters. When compared with nonhemiplegic side, there was no significant difference in VD and JD with a forearm cuff. But a humeral cuff showed significant difference in all parameters. So a forearm cuff type showed corrective effect this time. CONCLUSION: A forearm cuff type extension arm sling was a more effective orthosis for the reduction of the hemiplegic shoulder subluxation than a humeral cuff type extension arm sling.