The sacroiliac ligaments form the strongest ligament complex in the body, with the posterior sacroiliac ligaments in particular being exceptionally dense and robust. They collectively resist the nutation and counternutation forces at the sacroiliac joint, maintaining pelvic stability during gait, running, and lifting. The interosseous sacroiliac ligaments deep to the joint surface are the strongest and most important for joint stability, while the posterior long dorsal sacroiliac ligament is the most commonly symptomatic.
| Origin | Sacrum |
|---|---|
| Insertion | Posterior and anterior iliac surfaces |
| Actions | Stabilise the sacroiliac joint; resist shear, rotation, and distraction forces across the pelvis |
|---|
Sacroiliac joint pain affects 10 to 25 percent of patients with low back pain and is notoriously difficult to diagnose clinically because there is no single test with adequate sensitivity and specificity. A combination of provocation tests including FABER, thigh thrust, Gaenslen, and sacral compression provides better diagnostic accuracy than any single test. Sacroiliac joint injection under fluoroscopy or CT guidance confirms the diagnosis when three or more provocative tests are positive. Treatment includes manual therapy, stabilisation exercises, and joint injection.
Pain from the sacroiliac joint and its ligaments producing low back and buttock pain reproduced by a cluster of provocation tests, managed with stabilisation exercises, manual therapy, and diagnostic injections.
