The main ligaments supporting and holding the bony pelvis together are:
The ischiosacral ligaments create two openings in the pelvis:
- Greater sciatic foramen - located above the sacrospinous ligament, between the ilium, sacrotuberous and sacrospinous ligaments, ischial spine and the greater sciatic notch of the ischium; it contains the piriformis muscle, as well as vessels and nerves, such as the superior gluteal artery, vein and nerve, sciatic nerve and posterior femoral cutaneous nerve;
- Lesser sciatic foramen - located below the sacrospinous ligament, between the sacrospinous ligament, ischial spine and the lesser sciatic notch. The lesser sciatic foramen serves as a passage for the internal pudendal artery and vein, as well as the obturator internus muscle tendon and the nerve to the obturator internus.