Sacroiliac (SI) Joint Dysfunction

Location and behavior are the best initial clues. SI joint pain is characteristically a single, specific point just medial to the PSIS (the dimple on the back of the pelvis) — patients often point to it with one finger, which itself is a useful diagnostic clue called the "Fortin finger sign." It worsens predictably with one-leg standing, getting out of a car, rolling over in bed, and climbing stairs. Hip pain tends to be groin-dominant with rotation movements. Lumbar pain is typically higher and more diffuse. We use a cluster of provocation tests (FABER, FADIR, thigh thrust, compression) — three or more positive tests together are strongly predictive of SI joint involvement.

It can — SI joint pain frequently refers into the buttock, posterior thigh, and groin, and sometimes as far as the knee. What distinguishes it from lumbar nerve-root pain (sciatica) is the absence of the nerve-following stripe pattern and the typically absent neurological findings: reflexes, strength, and sensation are normal with pure SI joint dysfunction. The referred pain from the SI joint tends to be more diffuse and less sharp or electric than radicular pain. When we see leg pain combined with SI tenderness and positive provocation tests but normal neurological exam, the SI joint is the far more likely source.

Chiropractic care for pregnancy-related SI joint pain is both safe and effective, and it's one of the conditions we treat most frequently during pregnancy. Pregnancy hormones (particularly relaxin) increase ligamentous laxity in the pelvis, and the shift in center of gravity with a growing belly alters load on the SI joint significantly. We use modified positioning and gentle techniques appropriate for each trimester. Most pregnancy-related SI joint pain does improve significantly after delivery as relaxin levels normalize — but it can persist in the postpartum period, particularly if the birth involved prolonged pushing or a difficult labor, and responds well to treatment then as well.

Yes — unilateral pain below the belt line, localized to one side of the sacral dimple, is actually more characteristic of SI joint dysfunction than lumbar disc or muscle sources, which tend to be more central or bilateral. The SI joint transmits load asymmetrically between the two halves of the pelvis, and disruption of that symmetric transfer — from leg length difference, hip asymmetry, or a one-sided activity like running on a cambered road — tends to overload one joint while the other remains symptom-free. Bilateral SI joint pain exists but is less common and sometimes associated with inflammatory conditions like ankylosing spondylitis.

An SI belt can be genuinely helpful during acute flares or pregnancy by providing external compression that substitutes for the ligamentous stability the joint currently lacks. It's not a long-term crutch — think of it as a temporary scaffold while the active stability program takes hold. The concern about muscle weakening is real but manageable: we recommend using the belt during provocative activities (long walks, standing for extended periods) while doing your glute and core stabilization exercises without it. This way you're building the dynamic stability that should eventually replace the belt's support, rather than becoming dependent on it.