Is Your SI Joint the Missing Piece?

If you’ve ever dealt with nagging low back pain, hip discomfort, or even unexplained pelvic floor tension, the culprit might not be where you expect. One of the most overlooked players in the body is the sacroiliac joint—or SI joint—a small but powerful connector at the base of your spine.

The SI joint sits where your sacrum (that triangular bone at the bottom of your spine) meets your pelvis. Its main job is to provide stability while transferring force between your upper body and lower body. In other words, every time you walk, bend, or lift, your SI joint quietly keeps things running smoothly.

How It Shows Up When There’s a Problem

But when it’s not doing its job well, you’ll notice. SI joint dysfunction can cause pain that feels like it’s in the low back, hip, buttock, or even the groin. Some people describe it as a sharp jab when standing up or rolling in bed, while others feel a dull, lingering ache that makes daily movement uncomfortable. Because the pelvic floor and SI joint are closely connected through muscles and fascia, you might even notice symptoms like tension, pressure, or leaking when this joint is irritated.

So how does such a stable joint get thrown off balance? Pregnancy, postpartum changes, old injuries, or simply years of uneven posture and movement can all contribute. Sometimes it’s not just the pelvis itself—it’s the way the rest of the body is moving that puts extra strain on the SI joint.

Finding Relief

That’s why, as a physical therapist, I always take a whole-body approach to evaluating SI joint pain. I look at how your feet hit the ground, how your hips and glutes support you, how your rib cage moves when you breathe, and even how your posture higher up—like in your neck and shoulders—affects the chain of movement down into the pelvis. The SI joint rarely acts alone; it responds to the bigger picture.

The good news is that with the right treatment plan, SI joint pain is very manageable. In therapy, we work on restoring balance through strength and stability, releasing areas that are too tight, retraining posture and breathing, and making sure your everyday movements aren’t fueling the problem. When we treat the body as a whole, the SI joint finally gets the support it needs to calm down and do its job.

The Takeaway

If you’ve been chasing back, hip, or pelvic pain that just won’t go away, it might be time to consider the SI joint. Sometimes the smallest structures have the biggest impact—and with the right care, you can get back to moving comfortably and confidently.