SI Joint Pain: Is Your Back Pain Coming From Your SI Joint?

Most people have never heard of the sacroiliac (SI) joint until it starts to hurt. Yet you use it every time you walk, climb stairs or get out of the car. When it isn’t working well, it can cause lower back, buttock and even leg pain that’s easy to mistake for a disc problem or sciatica.

Here’s what the SI joint does, how we tell whether it’s the source of your back pain, and how SI joint physical therapy helps.

What Is the SI Joint?

You have two sacroiliac joints, one on each side, where the bottom of your spine (the sacrum) meets your pelvis. Unlike your knees or hips, the SI joints only tilt and rotate a tiny amount. That small amount of motion lets them do three important jobs:

• Stabilize and support your pelvis
• Transfer the weight of your upper body to your legs
• Absorb shock when you walk or run

Problems start when the joint moves too much (it becomes unstable) or too little (it becomes stiff). Either one can cause pain.

Signs Your SI Joint May Be the Problem

• Pain on one side of the lower back, low down near the top of the buttock
• Pain that stays below the lowest lumbar level and doesn’t sit in the middle of the spine or cross to the other side
• Pain in the buttock, hip or groin, sometimes spreading down the leg like sciatica
• Symptoms that started after a fall, accident or other trauma
• Pain with sitting for a long time, or at the end of your range of motion

Pregnancy and childbirth, weak pelvic or back muscles, scoliosis, a leg length difference and previous lower back surgery can all contribute.

How We Find Out If It’s Your SI Joint

Lower back pain can come from many places: the discs, the facet joints, the muscles, the vertebrae or the SI joint. That’s why a careful exam matters.

If your symptoms point toward the SI joint, we use SI joint provocation tests. These gently stress the joint to see whether they reproduce your pain. There are several of these tests, and when three or more are positive, the SI joint is likely the source. We also check whether your joint is moving too much or too little, because the treatment is different for each.

Because SI joint pain is so often confused with sciatica, read three conditions that mimic sciatica for how the two compare.

SI Joint Treatment and Physical Therapy

The goals are to restore normal joint motion and make the joint stable so the problem doesn’t come back.

• If the joint moves too much: stabilization exercises for the core, glutes and pelvis, and an SI joint belt to control excess motion during activity.
• If the joint is stiff: hands-on manual therapy and joint mobilization, plus mobility exercises.
• Pain relief: kinesiology tape, ice or heat, and other modalities to calm inflammation.
• A full plan: stretching, strengthening and aerobic exercise to keep it moving well.

Not every physical therapist treats SI joint pain the same way, so experience matters. Learn more about our sacroiliac joint treatment.

When to See a Doctor Right Away

• Loss of bladder or bowel control, or numbness in the groin
• Leg weakness that’s getting worse
• Pain with fever or after a significant fall or accident

Frequently Asked Questions

What does SI joint pain feel like?

Usually a dull ache on one side of the low back or buttock, sometimes spreading into the hip, groin or thigh.

Can SI joint pain feel like sciatica?

Yes. SI joint pain can spread down the leg, which is why testing is needed to tell them apart.

Does an SI belt help?

For a joint that moves too much, a belt can help control motion during activity, alongside stabilization exercises.

For more back pain causes, read common causes of lower back pain.

Get Your SI Joint Pain Evaluated

Start with our Fixing the Cause & Not Just the Symptoms Assessment, or Inquire About an Appointment →

Call our office at (239) 223-0484 to schedule your appointment.