If you have pain and instability in your lower back, especially when you get up from a chair, when you’ve been standing a long time, or when you’re climbing stairs, you may have a problem with the sacroiliac (SI) joint.
We have SI joints on both the left and right sides; they join the ilium—which is the big bone in the hip—with the sacrum, a triangle-shaped bone at the bottom of the spine. Pain from an SI joint can sometimes spread to the upper back, buttocks, or thighs.
There are a number of reasons you could have pain in an SI joint, including:
- Trauma from a car...