Fig. 1

3D printed partial hand prosthesis (Cyborg Beast 2). a shows the hand prosthesis in the open position. Elastic cords placed inside the dorsal aspect of the fingers provide passive finger extension. b Finger flexion is driven by non-elastic cords along the palmar surface of each finger and is activated through 20–30° wrist flexion of the residual functional joint. The red arrow shows the direction of wrist flexion to close the fingers and produce a functional grasp. c 3D printed partial hand prosthesis fitted to subject 2