The sacroiliac joint — or SI joint — connects your sacrum (the triangular bone at the base of your spine) to your pelvis. You have one on each side. Unlike most joints, the SI joint is designed primarily for stability, not movement. It absorbs shock between your upper body and legs with every step you take. Because it moves very little, even small changes in how it functions can cause significant pain.

SI joint pain is most commonly felt as a sharp or deep aching pain on one side of the lower back, just above the buttock. It can radiate into the hip, groin, or down the back of the thigh — but typically not below the knee. Many patients describe pain that gets worse when standing up from a chair, getting out of a car, climbing stairs, or rolling over in bed. Some describe a feeling of instability or "locking" in the pelvis.

SI joint pain is frequently mistaken for sciatica or a herniated disc because the symptoms overlap. The key differences are location and behavior. SI joint pain is usually felt on one side, centered near the dimple above the buttock, and does not typically travel below the knee. Sciatica from a herniated disc tends to radiate further down the leg and into the foot. Many patients with normal MRI results and failed sciatica treatments actually have undiagnosed SI joint dysfunction. A proper physical examination and diagnostic injection by a trained specialist is the only reliable way to tell the difference.

SI joint dysfunction is responsible for up to 30% of chronic lower back pain — yet it remains one of the most commonly missed diagnoses in medicine. There are several reasons. Standard imaging like MRI and X-ray rarely shows SI joint damage, even when the joint is the true source of pain. Most back pain protocols focus on the spine and discs, not the SI joint. And there is no single definitive test — diagnosis requires a combination of physical examination, patient history, and in many cases a diagnostic injection. The average patient sees five or more specialists over seven or more years before receiving a correct diagnosis.

SI joint pain can affect people of all ages and genders. Common causes include traumatic injury such as a car accident or fall, pregnancy and childbirth (hormonal changes loosen the SI joint ligaments), age-related wear and tear, repetitive stress from running or heavy lifting, prior lumbar spine surgery that shifts stress to the SI joint, and inflammatory conditions like ankylosing spondylitis. Women are more commonly affected than men, largely due to the effects of pregnancy on the joint.

SI Joint Relief is a referral service and does not diagnose medical conditions. Diagnosis is performed by the board-certified specialist you are matched with. According to leading spine organizations, the most reliable diagnostic approach combines a physical examination using specific SI joint provocation tests, a detailed patient history, and a diagnostic injection of a numbing agent into the joint under image guidance. If the injection significantly reduces pain, the SI joint is likely the source. Standard imaging is often used to rule out other causes.

SI Joint Relief does not provide medical treatment — all treatment decisions are made by the specialist you are matched with based on your individual diagnosis. Non-surgical options used by leading SI joint specialists typically include targeted physical therapy, anti-inflammatory medications, SI joint injections, radiofrequency ablation to quiet the nerves around the joint, and regenerative therapies. Minimally invasive surgical stabilization is available for patients who do not respond to conservative care. Our network prioritizes non-surgical approaches first.

Mild SI joint pain caused by a minor injury or temporary inflammation can sometimes improve with rest and conservative home care. However, chronic SI joint dysfunction — pain that persists for more than three months — rarely resolves without targeted treatment. Left unaddressed, SI joint instability can worsen over time and significantly impact your ability to work, sleep, and perform daily activities. Early diagnosis and treatment by a trained specialist gives patients the best chance at lasting relief.

Yes. Pregnancy is one of the most common triggers of SI joint dysfunction. During pregnancy, the body releases a hormone called relaxin that loosens the ligaments around the SI joint to prepare for childbirth. This increased flexibility can cause the joint to become unstable and painful — both during pregnancy and after delivery. Postpartum SI joint pain is frequently misattributed to general back pain or dismissed as a normal part of recovery. If you experienced low back or pelvic pain during or after pregnancy that has not resolved, SI joint dysfunction may be the cause.

A simple self-check used by many specialists is the Fortin Finger Test — pointing with one finger to the exact location of your pain. If you consistently point to a spot within a few centimeters of the dimple just above your buttock, on one side, SI joint involvement is strongly suspected. Other indicators include pain that worsens when transitioning from sitting to standing, discomfort sleeping on the affected side, and pain that has persisted despite normal imaging results and standard back pain treatments. Only a trained specialist can confirm the diagnosis — and that is exactly what we help you find.

Yes — using SI Joint Relief to find a specialist is completely free. Our referral service costs you nothing. We match you with a vetted, board-certified SI joint specialist in your area at no charge. Once you connect with a provider, standard medical fees apply. Most participating specialists accept major insurance plans, and out-of-pocket costs vary by provider, location, and your individual coverage. We recommend confirming insurance and fee details directly with your matched provider before your appointment.

Most participating specialists in our network accept major insurance plans including Medicare, Blue Cross Blue Shield, Aetna, Cigna, United Healthcare, and others. However, coverage varies by provider, location, and your individual plan.

SI Joint Relief is a free referral service — we are not a medical provider and do not bill insurance directly. Once we match you with a specialist near you, we recommend contacting their office directly to confirm accepted insurance plans and any out-of-pocket costs before your appointment.

If you are uninsured or underinsured, many of our participating providers offer self-pay rates and flexible payment options.