Sacrospinous ligament

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The sacrospinous ligament is a stabilizer of the sacroiliac joint and connects the bony pelvis to the vertebral column.

Gross anatomy

The sacrospinous ligament is a triangular-shaped structure with its base attached to the anterior sacrum (S2-S4) and coccyx, and its apex attached to the ischial spine. It forms a boundary of the greater and lesser sciatic foramen.

Relations

  • anteriorly: coccygeus muscle 
  • posteriorly: sacrotuberous ligament, crossed by internal pudendal vessels and nerves
  • superiorly: upper margin forms the lower border of the greater sciatic foramen
  • inferiorly: lower margin forms part of upper border of the lesser sciatic foramen