Pelvic stability: pelvic ligaments
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The pelvis
The pelvis is formed by the sacrum, coccyx and a pair of innominate bones. The innominate bones are formed by the fusion of 3 bones (pubis, ilium and ischium). | |
Sacroiliac joint
The sacroiliac joint is a synovial joint. It is reinforced by a number of ligaments:
- Sacrotuberous ligament
- Sacrospinous ligament
- Iliolumbar ligament
- Sacroiliac ligaments (anterior and posterior)
Key ligaments contributing to stability of the SIJ
| Ligament | Origin | Insertion |
|---|---|---|
| Sacrotuberous ligament | sacrum | tuberosity of the ischium |
| Sacrospinous ligament | Ischial spine | sacrum |
| Iliolumbar ligament | Transverse process of fifth lumbar vertebra | Posterior part of iliac crest |
| Sacroiliac ligaments | Sacrum | Ilium |
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Anterior view of the pelvis: overview of the pelvic ligaments contributing to pelvic stability
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View with lateral angulation highlighting sacrotuberous and sacrospinous ligaments
Sacrococcygeal joint
Cartilaginous joint between sacrum and coccyx. It is also called the sacrococcygeal symphysis and features a sacrococcygeal disc between the sacrum and coccyx. The joint is reinforced by dorsal, ventral and lateral sacrococcygeal ligaments.