High Quality Content by WIKIPEDIA articles! The sacrospinous ligament (small or anterior sacrosciatic ligament) is thin, triangular ligament attached by its apex to the ischial spine, and medially, by its broad base, to the lateral margins of the sacrum and coccyx, in front of the sacrotuberous ligament with which its fibers are intermingled.Together with the sacrotuberous ligament, it converts the greater sciatic notch into the greater sciatic foramen and the lesser sciatic notch into the lesser sciatic foramen.[1] The lateral part of its upper border forms the lower boundary of the greater foramen, while the lateral part of its lower border forms the upper part of the lesser foramen. Its posterior half is covered by the sacrotuberous ligament, and in its entire length it covers the equally triangular coccygeus muscle, to which its closely connected.