Ligaments of the pelvis (Posterior view) (English)

The sacroiliac joint is strengthened by three ligaments, namely the anterior (see previous image), interosseous and posterior sacroiliac ligaments. The interosseous sacroiliac ligament constitutes the major bond between the ilium and sacrum, filling the gaps between these two bones at the posterosuperior aspect of the joint. The posterior sacroiliac ligament lies superficial to the interosseous sacroiliac ligament and consists of several fibers connecting the posterior superior iliac spine (PSIS), iliac crest as well as the lateral and intermediate sacral crests. The two bones of the pelvic spine (sacrum and coccyx) are strengthened by the anterior (see previous image) and posterior sacrococcygeal ligaments. The superficial posterior sacrococcygeal ligament arises from the margin of the sacral hiatus and attaches to the dorsum of the coccyx. The deep posterior sacrococcygeal ligament extends from the dorsal surface of the fifth sacral vertebral body to the dorsal surface of the coccyx. Bilaterally, the lateral posterior sacrococcygeal ligament spans from the inferolateral angles of the sacrum to the transverse processes of the coccyx. Two major ligaments situated on the posterior aspect of the bony pelvis are the sacrospinous and sacrotuberous ligaments. These transform the lesser and greater sciatic notches into the lesser and greater sciatic foramina. The former extends from the margins of the coccyx and sacrum to the spine of the ischium, while the latter has several attachments to the posterior superior iliac spine, the posterior sacroiliac ligaments, lateral sacral crest as well as the lateral margins of the lower sacrum and upper coccyx.Lastly, the posterior pubic ligament, blending with the periosteum of both pubic bodies posteriorly, can equally be seen in this view.