1 — Metacarpal [II]; 2 — Extensor indicis; 3 — Extensor pollicis longus; 4 — Posterior border; 5 — Ulna; 6 — Groove for ulnar nerve; 7 — Medial epicondyle; 8 — Lateral epicondyle; 9 — Olecranon; 10 — Supinator; 11 — Radius; 12 — Abductor pollicis longus; 13 — Extensor pollicis brevis; 14 — Dorsal tubercle; 15 — Base of metacarpal [I]; 16 — Metacarpal [I]; 17 — Proximal phalanx [I], base of phalanx; 18 — Distal phalanx [I],
base of phalanx