Fig. 23. Tendon injury zones. Left: flexor tendon zones. These represent 1: the forearm; 2: carpal tunnel; 3: palm; 4: digital sheath containing two tendons; 5: digital sheath containing one tendon. Right: extensor tendon zones. These correspond to 1: distal interphalangeal joint; 3: proximal interphalangeal joint; 5: metacarpophalangeal joint; 7: wrist; 2,4,6,8: sections in between.