Between 15% and 30% of people with chronic lower back pain have a problem that is not a disc, not sciatica, and not a muscle strain. The culprit is a small, strong joint most people have never thought about: the sacroiliac joint.
The sacroiliac joint, or SI joint, sits where your lower spine meets your pelvis. You have one on each side. It does not move much, which is the point. It is built to be stable. But when it shifts even slightly out of position, the pain can be intense and hard to locate.
Key Stat: Up to 30% of patients with axial lower back pain have sacroiliac joint dysfunction as the primary cause, according to 2025 multispecialty consensus guidelines published in Pain Medicine.
What Does SI Joint Pain Feel Like?
SI joint pain usually shows up as a dull ache just below the beltline, on one side. It often spreads into the buttock, hip, or upper thigh. Some people feel it in the groin.
It can feel similar to sciatica. But there is an important difference. Sciatica typically causes a burning or shooting sensation that travels past the knee. SI joint pain usually stops above the knee.
You may notice it most when getting out of a car after a long drive, rolling over in bed, walking up stairs, or standing on one leg. Morning stiffness is common. Many people describe it as “deep and hard to locate.” That vagueness is part of why it often goes undiagnosed.
What Causes SI Joint Dysfunction?
The SI joint bears the weight of your entire upper body with every step. Several things can knock it out of balance.
Repetitive one-sided activity is a common trigger. Gardening, golf, and running all put uneven force on the SI joint. Summer is a frequent trigger season for this reason.
Leg length differences change how the pelvis tilts, which alters how the SI joint loads with each step. Pregnancy loosens the ligaments around the pelvis, which can make the joint unstable.
A prior disc herniation or lumbar surgery can also shift how forces travel through the spine, putting extra stress on the SI joint over time.
How Is SI Joint Dysfunction Diagnosed?
There is no single definitive test. Imaging such as X-ray or MRI usually looks normal or shows only mild changes. That is one reason it gets missed.
Diagnosis relies mostly on physical examination. A clinician uses a series of movement and pressure tests called provocative tests. A 2024 review in Pain Practice found that when three or more of these tests are positive together, the combined sensitivity and specificity are reasonably high. No single test tells the whole story.
What Actually Helps SI Joint Pain?
Most cases respond well to conservative care without surgery.
A 2024 systematic review and meta-analysis in the Journal of Manual and Manipulative Therapy analyzed 16 randomized controlled trials with 421 adults. Researchers found that manual therapy produced a statistically significant moderate effect in reducing disability in people with SI joint pain (SMD: -0.67). That is a meaningful improvement in daily function.
Manual therapy and spinal manipulation. A chiropractor or physical therapist can use specific techniques to restore normal movement to the SI joint and surrounding structures. This approach is also useful when the whole spine is involved, as with cervicogenic headaches that originate in the neck and pelvis.
Targeted strengthening exercises. Building the gluteus medius and deep core stabilizers takes pressure off the SI joint and reduces the risk of flare-ups.
Activity modification. Temporarily cutting back on the activity that triggered the pain gives the joint time to calm down.
Corticosteroid injections. For cases that do not respond to conservative care, injections into or around the joint can provide several weeks of relief and allow active rehabilitation to take hold.
Simple Exercises to Try Right Now
Three movements are commonly recommended for SI joint stability:
- Clam shells: Lie on your side, knees bent. Lift the top knee as if opening a clamshell. Hold two seconds. Do 10 to 15 reps per side.
- Bridge with squeeze: Lie on your back, knees bent. Place a folded towel between your knees and squeeze it. Lift your hips off the floor. Hold three seconds. Do 10 reps.
- Standing hip hinge: Stand on one foot, hinge forward at the hip while keeping your back flat. Return to standing. Alternate sides. Do 8 reps per leg.
Start gently. If any movement causes sharp or worsening pain, stop and consult a clinician before continuing.
The Bottom Line
SI joint dysfunction is more common than most people realize. It causes real, disabling lower back pain that often gets misattributed to sciatica or a disc problem. The good news is that it responds well to conservative treatment, including manual therapy, targeted exercise, and activity modification.
If your lower back pain is one-sided, sits just below your beltline, and has not improved with standard treatments, the SI joint is worth investigating. Getting an accurate diagnosis is the first step toward lasting relief.
Sources & Further Reading
- McCormick ZL, et al. Consensus practice guidelines on sacroiliac joint complex pain from a multispecialty, international working group. Pain Medicine. 2025;26(12):817-917. https://doi.org/10.1093/pm/pnaf129
- Szadek K, et al. Sacroiliac joint pain. Pain Practice. 2024;24(4):627-646. https://doi.org/10.1111/papr.13338
- Trager RJ, et al. Efficacy of manual therapy for sacroiliac joint pain syndrome: a systematic review and meta-analysis of randomized controlled trials. Journal of Manual & Manipulative Therapy. 2024;32(6):561-572. https://doi.org/10.1080/10669817.2024.2316420
- Janapala RN, et al. Systematic review and meta-analysis of the effectiveness of radiofrequency ablation of the sacroiliac joint. Current Pain and Headache Reports. 2024;28(5):335-372. https://doi.org/10.1007/s11916-024-01226-6
