I — Ischial tuberosity; 2 — Sacrotuberous ligament; 3 — Coccyx [coccygeal vertebrae CoI-CoIV]; 4 — Ischial spine; 5 — Sacral hiatus; 6 — Sacrospinous ligament; 7 — Anterior sacro-iliac ligament; 8 — Sacrum [sacral vertebrae SI-SV]; 9 — Sacral canal; 10 — Spinous process;
II — Intervertebral disc; 12 — Promontory; 13 — Anterior superior iliac spine; 14 — Greater sciatic foramen; 15 — Arcuate line; 16 — Pecten
pubis; Pectineal line; 17 — Lesser sciatic foramen; 18 — Symphysial surface; 19 — Obturator membrane
