SI Joint Pain

SI Joint Pain: What It Feels Like and How to Tell

What does SI joint pain feel like?

Most people describe a deep ache on one side of the low back, low enough that they point below the belt instead of at the spine. In one study of 50 patients whose pain was confirmed with an injection into the joint, 94% felt it in the buttock and 72% in the lower back.

Half of that group also had pain in the leg, and 28% felt it below the knee, so leg pain alone doesn't rule the SI joint out. Groin pain showed up in 14%. The moments that set it off tend to be the ones that load one side of the pelvis at a time: standing up after sitting, getting out of the car, rolling over in bed, taking stairs, or standing on one leg to put on your pants.

One tell we pay attention to: ask someone with SI joint pain where it hurts, and they'll often point with one finger to a spot just below that dimple. Pain that spreads across the whole low back, or runs straight down the middle, usually points somewhere else.

What does a stuck or locked SI joint feel like?

A stuck SI joint usually feels like one side of your pelvis won't move with the other. People describe a catch when they stand up, stiffness for the first few steps, or a sense that one hip sits higher than the other. The joint itself only moves a couple of degrees, so most of what you feel is the muscle around it guarding that small motion.

That small motion is why the word "locked" can mislead. Tracked with precise x-ray measurement, the SI joint rotated about 2.5 degrees on average and slid less than a millimeter. It doesn't lock like a door. It stops gliding the way it should, and the muscles around it tighten to protect it. That's also why it can feel like it pops back in when you twist, and why that feeling tends to fade.

Is it your SI joint or something else?

A disc problem can hurt in the same low back and buttock area as SI joint pain, and so can the hip joint. Sometimes two of them show up together. A few patterns help separate them, but none of them settles it alone. That's why we test the joint directly instead of going by where it hurts.

SI joint pain tends to sit on one side, below the belt line, and it often starts after a specific event, like a fall, a missed step off a curb or lifting something at an awkward angle.

Disc pain tends to sit closer to the middle of the back, and it often gets worse bending forward or sitting for a long stretch. When a disc irritates a nerve, the leg symptoms usually come with numbness or tingling in a strip down the leg. That pattern points toward sciatica more than the SI joint.

Hip joint pain more often shows up in the front of the hip or the groin, and it tends to hurt when you rotate the leg, like crossing one ankle over the opposite knee.

How do we confirm it's your SI joint?

We use a set of hands-on tests that stress the joint from different directions, then check your standing x-ray. No single test is reliable enough on its own. In one study, three or more positive tests out of six caught 94% of confirmed SI joint cases, and when none of the six reproduced the pain, the SI joint could be ruled out.

The x-ray adds what the exam can't. On your standing x-ray we measure whether each side of the pelvis has shifted forward, backward, in or out, and the height of each femur head. Those numbers tell us which direction to adjust, and they come up before every adjustment, on every visit.

If one femur head sits more than 3 mm higher than the other, or the short leg is on a side that doesn't make mechanical sense, we order a full leg length study. Our video post shows how we determine leg length discrepancy with x-rays.

Can you adjust your own SI joint at home?

Not the way an adjustment works in the office, and the reason is direction. An SI joint can get stuck with that side of the pelvis shifted forward or shifted backward, and the adjustment for one runs opposite to the other. We read that direction off a standing x-ray before anyone adjusts.

The twist-and-pop most people try at home tends to move the joints that already move easily, which is why the relief fades. There's more on that in our post on whether you can crack your own back. What does help at home is keeping your hip rotators and hamstrings loose, since tight ones keep pulling the pelvis back toward the same position. If you run, our post on SI joint pain in runners walks through those stretches with video.

How SI joint pain gets treated here

Your first visit is an exam and a standing x-ray. The first adjustment comes at the second visit, after we walk you through what the numbers show. From there we adjust to the direction your pelvis actually shifted, and every doctor in all three of our Houston offices works from the same x-ray notes on you.

When the discs are part of the picture too, we add spinal decompression in a seated chair. You sit upright, fully clothed, with no straps, for 10 minutes. For tight muscle deep in the hip we use PEMF therapy or HEIT therapy. We also show you the stretches and exercises you need, so you can do them at home. This saves you time and money.

If this page sounds like your back, you can schedule online and we'll start with your standing x-ray.

SI joint pain questions

Why does my SI joint pain keep coming back after adjustments?

Usually because something keeps pulling the pelvis back out of level. An SI joint doesn't hold when the pelvis it sits in is unlevel. Leg length is one of the first things we check: if one leg is shorter, that side of the pelvis sits lower with every step, and the joint takes the same load again. A large review lists both true and apparent leg length differences among the known risk factors for SI joint pain, which is why we measure it instead of assuming it.

How do you keep your SI joint in place?

By dealing with whatever keeps shifting it. That means adjusting to the direction the pelvis actually moved, then finding what moves it again, whether that's a leg length difference or hip rotators tight enough to tug one side of the pelvis. Visits space out as the joint starts holding its position between them.

Can SI joint pain go down your leg?

Yes. In the injection study above, half the patients had leg pain and 28% felt it below the knee. SI joint pain in the leg tends to be a deep ache rather than the sharp, electric feeling of an irritated nerve. When we see numbness or tingling in a clear strip down the leg, we look at the lower back first.

Is it bad to pop your SI joint?

An occasional pop isn't dangerous. The sound is gas releasing from the fluid inside the joint. The catch is that the pop you get from twisting usually comes from the joints that already move freely, not the stuck one, so the relief fades quickly. If you're popping it every day just to get through the day, that's a good sign it needs to be measured.

Does SI joint pain show up on an x-ray?

The pain doesn't. The position does. A standing x-ray shows whether each side of the pelvis has shifted and whether the femur heads sit level, which tells us how to adjust. It can also show arthritis in the joint. Whether that position is what's causing your pain is the question the hands-on tests answer.

Where these numbers come from: the pain locations come from Sacroiliac joint pain referral zones (Slipman, 2000). The test accuracy comes from Diagnosis of sacroiliac joint pain: validity of individual provocation tests and composites of tests (Laslett, 2005). The joint's range of motion comes from Movements of the sacroiliac joints. A roentgen stereophotogrammetric analysis (Sturesson, 1989). The leg length risk factor comes from Sacroiliac joint pain: a comprehensive review of epidemiology, diagnosis and treatment (Cohen, 2013).