1 — Trochlear notch; 2 — Coronoid process; 3 — Radial notch; 4 — Tuberosity of ulna; 5 — Shaft of ulna; Body of ulna, anterior surface; 6 — Interosseous border; 7 — Articular circumference; 8 — Head of ulna; 9 — Ulnar styloid process; 10 — Olecranon; 11 — Posterior border; 12 — Shaft of ulna; Body of ulna, posterior surface;13 — Shaft of ulna; Body of ulna, medial surface