Abstract: A locking shoulder joint adapted to be attached to a user's shoulder, generally comprising a rotor provided with a plurality of radially positioned pins, that rotates relative to a stator, and a cam provided with one or more plungers adapted to engage said rotor pins to releasably lock said rotor in position selected by said user, all of which act to move a humeral member in a direction corresponding to a flexion/extension direction of the shoulder joint; and a yoke coupled to an axle for moving the humeral member in a direction corresponding to an abduction/adduction direction of the shoulder joint.