Sacroiliac joint dysfunction generally refers to pain in the sacroiliac joint region that is caused by abnormal motion, either too much motion or too little motion, in the sacroiliac joint. It typically results in inflammation of the sacroiliac joint and can be debilitating. Leg pain from sacroiliac joint dysfunction can be particularly difficult to differentiate from radiating leg pain caused by a lumbar disc herniation (sciatica) as they can feel quite similar.
The sacroiliac joint connects the hip bones (iliac crests) to the sacrum, the triangular bone between the lumbar spine and the tailbone (coccyx). The primary function of the sacroiliac joints is to absorb shock between the upper body and the pelvis and legs.
The primary causes of Sacroiliac joint dysfunction include:
- Too much movement - (hypermobility or instability) in the sacroiliac joint can cause the pelvis to feel unstable and lead to pain. Pain from too much motion is typically felt in the lower back and/or hip, and may radiate into the groin area.
- Too little movement - (hypomobility or fixation) can cause muscle tension, pain, and may inhibit mobility. Pain is typically felt on one side of the low back or buttocks, and it can radiate down the back of leg (similar to sciatica pain).