1 — Urogenital hiatus; 2 — Iliococcygeus; 3 — Pubic symphysis; 4 — Obturator canal; 5 — Tendinous arch of levator ani; 6 — Obturator internus; 7 — Ischial spine; 8 — Piriformis; 9 — Anterior superior iliac spine; 10 — Iliac crest; 11 — Sacro-iliac joint; 12 — Posterior superior iliac spine; 13 — Ala; Wing; 14 — Sacrum [sacral vertebrae SI-SV]; 15 — Ischiococcygeus; Coccygeus; 16 — Coccyx [coccygeal vertebrae CoI-CoIV];17 — Puborectalis; 18 — Anal aperture; 19 — Pubococcygeus
