Greater sciatic foramen

The greater sciatic foramen is a complete opening found along the posterior border of the hip bone or ilium. It is formed by the sacrospinous and sacrotuberous ligaments in the lateral wall of the pelvis, which transform the incomplete greater sciatic notch into a full-fledged foramen.

The greater sciatic foramen is bounded by several structures:

• The antero-superior boundary is formed by the greater sciatic notch, extending from the posterior inferior iliac spine to the ischial spine.

• The inferior boundary is provided by the sacrospinous ligament, extending from the ischial spine to the sacrum.

• The postero-superior boundary is formed by the sacrotuberous ligament, extending from the ischial tuberosity to the sacrum.

Various important anatomical structures pass through the greater sciatic foramen, entering from the pelvic cavity into the gluteal region. These structures include the piriformis muscle, the superior and inferior gluteal vessels and nerves, nerves supplying the deep lateral rotators of the hip joint (such as piriformis, obturator internus, superior and inferior gemelli, and quadratus femoris), the sciatic nerve, pudendal nerves and vessels, and the posterior cutaneous nerve of the thigh.