1 — Coccyx [coccygeal vertebrae CoI-CoIV]; 2 — Anococcygeal body; Anococcygeal ligament; 3 — Obturator internus; 4 — Tendinous arch of levator ani; 5 — Iliococcygeus; 6 — Ischial spine; 7 — Ischiococcygeus; Coccygeus; 8 — Piriformis; 9 — Sacrum [sacral vertebrae SI-SV]