The present invention provides an orthotic appliance for the carpus of a human hand for the treatment of a carpal tunnel syndrome condition using co-dynamic, rather than traditional static or dynamic, techniques. The appliance may apply a dorsally-directed force to the region of the pisiform bone (23) in the neutral carpal position of a human hand upon co-contraction of the hand and up to 8 pounds dorsally-directed during arc of motion in carpal flexion, as the wrist and hand is encouraged to actively move in all planes of motion without restricting arc of motion or negatively affecting the normal activities of daily living. The appliance may comprise a biasing structure for applying the dorsally-directed force and a base structure for maintaining the biasing structure in its proper configuration during normal hand motion.