Sacrotuberous Ligament

The posterior surface of the Sacrotuberous Ligament gives origin to the gluteus maximus muscle. Its anterior surface is in part united to the sacrospinous ligament. Its upper border forms, above, the posterior boundary of the greater sciatic foramen, and, below, the posterior boundary of the lesser sciatic foramen. Its lower border forms part of the boundary of the perineum. The sacrospinous ligament is covered anteriorly by the coccygeus muscle. It is crossed posteriorly by the internal pudendal vessels and pudendal nerve. Its upper border forms the lower boundary of the greater sciatic foramen; its lower border, part of the margin of the lesser sciatic foramen. These two ligaments convert the sciatic notches into foramina. The greater sciatic foramen is bounded, behind, by the sacrotuberous ligament, and below, by the sacrospinous ligament. The lesser sciatic foramen is bounded, above, by the sacrospinous ligament; behind, by the sacrotuberous ligament. It transmits the tendon of the obturator internus muscle, and the internal pudendal vessels and pudendal nerve.