Vertebro-pelvic ligaments are bands connecting the vertebrae of the spine with the pelvis, which stabilize mainly the lumbosacral joint.

The main ligaments supporting and holding the bony pelvis together are:

• Ischiosacral ligaments:
  • Sacrospinous ligament
  • Sacrotuberous ligament
• Iliolumbar ligament

Ischiosacral ligaments

Ischiosacral ligaments stretch between the ischium and sacrum, and include two very important ligaments - sacrospinous ligament and sacrotuberous ligament.

They aid in maintaining the sacrum in its anatomical position at rest and during exercises. Both ligaments also prevent rotation of the ilium and provide stability to the sacroiliac joint.

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.