Sacroiliac — or SI — joint pain isn’t fun. If you’ve got arthritis of the pelvis, are pregnant and have loose pelvic bones, or have suffered a traumatic accident or infection that affect your SI joint, everyday actions can have a fairly profound effect on your pain. Sitting down or standing up, for example, can suck. To a degree, the simple motion of the action can cause some discomfort, but sitting in the wrong chair makes things dramatically worse.
Why Does the Sacroiliac Joint Hurt In the First Place?
The SI joint is a very tight joint between the two sides of the pelvis (the ilium) and the solid bone that acts as the terminus of your spine (the sacrum, which sits between the coccyx — tailbone — and the lowest lumbar vertebra.) Scientists used to believe that the SI joint was of the ‘fixed’ variety like the joint between the bones of your skull, but they’ve recently learned that there are a few degrees of movement that can happen in the SI joint.
When the joint is able to (due to pregnancy hormones causing the ligaments in the pelvis to loosen) or forced to (generally by outside force like a fall or car accident) move beyond those few degrees, it hurts. Simply put, the muscles around the SI joint don’t flex that way, and making them try isn’t a pleasant experience.
So How Can a Chair — Even the Best Chair for Si Joint Pain — Help?
You might think that if the problem is that the SI joint is moving too much, there’s not a lot you can do about it — there’s no such thing as an “SI splint,” after all. And to a degree, you’re correct — when you’re moving about, especially bending over or taking other actions that cause the load on your SI joint to shift, there’s little you can do except wince through it. But when you’re seated, you do have one good option: perfect lumbar support.
The most common reason the SI joint flexes is because the weight held by your spine shifts from being normally supported by the lumbar and thoracic curves into some abnormal position (like leaning forward so that your inward lumbar curve shifts outward instead.) If you can manage to find a chair that offers lumbar support that is not only right for sitting, but maintains the same support as you move around in your chair, you’ve found the best chair for SI joint pain.
Do Chairs Actually Do That?
Certainly. A few modern chairs have what’s called a Dynamic Counterbalance system that causes the lumbar support and seat pan to shift in harmony with your back, butt, and thighs as you lean forward, lean backward, stretch, and relax. After setting the various adjustments so that the lumbar support is perfectly aligned with your lumbar curve, such a chair offers the best chance at avoiding triggering your SI joint pain.