In 10 cadaver shoulder joints, the increments in external rotation were measured after successive cutting of the anterior stabilizing structures while a constant external torque was applied to the humerus, abducted in the scapula plane. The subscapularis muscle prevented anterior subluxation in the lower range of abduction. As abduction increased, the lower part of the capsule was the most important stabilizing structure. The findings suggest that it may be possible to perform more selective repairs in the treatment of recurrent anterior instability.