SI joint pain usually sits low and to one side of the back, right over the bony dimple near your belt line, and gets worse with rolling over, stairs or standing on one leg. Sciatica is nerve pain that tends to shoot down the back of the leg, often past the knee, and may bring tingling or numbness.
By Dr. Orr Soffer, DC · Chiropractor in Campbell, CA
The two get mixed up all the time because both can hurt in the buttock. Below you’ll find a five-clue self-check you can do in a few minutes today, what the research says about telling them apart, and what actually helps each one.
Why Do SI Joint Pain and Sciatica Feel So Similar?
Your sacroiliac (SI) joints connect the base of the spine to the pelvis, one on each side. The sciatic nerve forms from nerve roots in the low back and runs right past that area, through the buttock and down the leg. Same neighborhood, different tenants.
When the SI joint is irritated, it can refer a deep ache into the buttock, the side of the hip, the groin and sometimes the thigh. When a lumbar nerve root is irritated, usually by a disc or narrowing around the nerve, the pain follows the nerve’s path. Both can start in the buttock, which is exactly why “my sciatica is acting up” is one of the most common things people tell me, and why it’s often the SI joint instead.
This matters because the plans differ: an irritated nerve needs calming, while an SI joint usually needs the pelvis loaded and stabilized. Treating one like the other keeps people stuck.
What Does SI Joint Pain Usually Feel Like?
According to a review in American Family Physician, SI joint dysfunction is behind roughly 25% of chronic low back pain in adults. The pain is usually not in the middle of the spine. It sits at or just below and inside the posterior superior iliac spine, the bony bump under the dimple at the back of your pelvis, and can spread into the buttock, outer hip, groin or leg.
Common patterns we see:
- One-sided ache low in the back, often described as “deep” or “in the joint”
- Worse when rolling over in bed, climbing stairs, getting out of a car or standing on one leg to put on pants
- Stiff after sitting, then a sharp catch on the first few steps
- Usually no tingling, numbness or leg weakness
What Does Sciatica Usually Feel Like?
The Mayo Clinic describes sciatica as pain that follows the nerve from the low back through the buttock and down the back of the thigh and calf. It’s usually on one side and can range from a dull ache to burning or an electric jolt. Many people also notice numbness, tingling or weakness in the leg or foot.
Clues that lean toward a nerve root:
- Pain travels below the knee, sometimes into the foot
- The leg hurts more than the back
- Coughing, sneezing or long stretches of sitting make it worse
- Pins and needles, numb patches or a foot that slaps or feels weak
“Sciatica” describes symptoms, not a diagnosis. The question is always what is irritating the nerve, which is why we look at the whole picture rather than the label. If you want a deeper look at the nerve side, our post on musculoskeletal pain vs nerve pain covers how the two behave differently.
The 5-Clue Self-Check You Can Do Today
This won’t diagnose you, but it gives you useful notes to bring to a visit. Write your answers down.
- The one-finger test. Stand up and point to the worst spot with one finger. If you land within about a finger’s width of the bony bump under your back dimple, that leans SI joint. Clinicians call this the Fortin finger test. If you can’t point to one spot because it runs down the leg, that leans nerve.
- Trace the line. Run your hand along where the pain goes. Stops at the buttock or upper thigh: more SI-like. Continues past the knee into the calf or foot: more nerve-like.
- The cough check. Give one firm cough or note what happens when you sneeze. A sharp zing down the leg points toward a nerve root. No change, or only a mild local ache, is more typical of the SI joint.
- The one-leg check. Hold a counter and stand on the painful-side leg for 10 seconds, then the other side. Sharp pain at the back of the pelvis on the loaded side leans SI. Stop if pain shoots down the leg.
- Skin and strength. Lightly brush both shins and feet with your fingertips. Then walk 10 steps on your heels and 10 on your toes. A numb patch, or one side that can’t hold heels or toes, is a nerve sign and worth getting checked soon.
Here’s how the answers usually sort out:
| Clue | Leans SI joint | Leans sciatica |
|---|---|---|
| Where you point | One spot near the back dimple | A line down the leg |
| How far it goes | Buttock, hip, upper thigh | Below the knee, calf, foot |
| Cough or sneeze | Little change | Zing down the leg |
| Standing on one leg | Pain at the back of the pelvis | Often no change |
| Numbness or weakness | Usually none | Often present |
Mixed answers are common. Plenty of people have an irritated SI joint and a grumpy nerve at the same time, which is why a hands-on exam matters.
How Do Clinicians Tell Them Apart?
No single test is reliable on its own. What works is a cluster. The American Family Physician review describes five SI provocation tests (distraction, thigh thrust, compression, sacral thrust and Gaenslen’s). When three or more reproduce your familiar pain, SI joint dysfunction becomes a reasonable working diagnosis. Earlier work by Laslett and colleagues in Manual Therapy also found that when none of the provocation tests reproduce familiar pain, the SI joint can be ruled out as the current source.
On the nerve side, we check reflexes, sensation and strength in specific muscle groups, and use nerve-tension tests such as the straight leg raise and slump test. We also look at how your low back moves, because disc-related pain often changes with repeated bending or extension.
How We Treat SI Joint Pain and Sciatica at The ChiropractOrr
Your first visit starts with a conversation and a full exam, including the tests above, so we know which problem we’re dealing with before we treat anything. From there we follow our Offload → Rebuild → Reeducate approach.
For SI joint pain: the AAFP review lists exercise and SI joint manipulation as first-line care, with manipulation helping in the short term and the combination with exercise giving longer-lasting results. In practice that means a chiropractic adjustment to the pelvis or low back when it fits, soft tissue work on the glutes and hip, and then a progressive plan for hip and core stability. Once you’re past the irritable phase, our post on advanced exercises to stabilize the SI joint shows where that plan heads.
For sciatica: we focus on calming the nerve. That can include positions and movements that ease leg symptoms, gentle nerve-gliding, soft tissue therapy for the surrounding muscles, adjustments where appropriate, and a gradual return to sitting, walking and lifting. Our article on how chiropractic care treats sciatic nerve pain goes into more detail.
Either way, you leave with a personalized rehab exercise plan built from your exam, not a generic sheet. Visits are in-clinic in Campbell, and if driving or sitting in the car is the problem right now, our mobile chiropractic visits come to you in Los Gatos, Saratoga, San Jose and nearby.
When to See a Doctor First
Call 911 or go to an emergency room for:
- New trouble controlling your bladder or bowels, or numbness in the groin or inner thighs
- Sudden or worsening weakness in a leg, or a foot that suddenly drags
- Back or leg pain after a major trauma such as a car crash or a hard fall
See your physician promptly if you have back pain with fever, unexplained weight loss, a history of cancer, night pain that doesn’t ease with any position, or pain that keeps getting worse after a week of sensible self-care. If you’re unsure whether your pain calls for rest or care, our guide on whether back pain needs treatment or rest walks through the decision.
Key Takeaways
- SI joint pain usually stays near the back dimple, buttock and upper thigh and flares with stairs, rolling over and single-leg standing.
- Sciatica tends to travel below the knee and often brings tingling, numbness or weakness.
- No single test settles it. A cluster of exam findings does.
- Exercise, with or without manipulation, is the recommended first step for SI joint dysfunction.
- Bladder or bowel changes, or sudden leg weakness, need emergency care.
FAQ
Can SI joint dysfunction cause pain down the leg?
Yes. An irritated SI joint can refer pain into the buttock, outer hip, groin and thigh, which is why it gets mistaken for sciatica. Pain that travels well below the knee with tingling or numbness points more toward a nerve root.
Can you have SI joint pain and sciatica at the same time?
Yes, and it’s fairly common. A sore SI joint and an irritated nerve root can overlap, so the exam needs to check both. Treatment then addresses each piece in order of what is driving the most symptoms.
Does sitting make SI joint pain or sciatica worse?
Both can flare with sitting. Sciatica often builds the longer you sit, while SI joint pain tends to catch when you stand up and take the first few steps. Short movement breaks every 30 to 45 minutes help with either.
Can a chiropractor help SI joint pain?
Often, yes. A review in American Family Physician recommends exercise, SI joint manipulation or both as first-line care, with the combination giving longer-lasting results than exercise alone. A good plan pairs hands-on care with strengthening.
Do I need an MRI to tell SI joint pain from sciatica?
Usually not at first. A careful history and physical exam answer the question for most people. Imaging becomes useful when there are neurological changes, red flags, or pain that isn’t improving with a solid plan.
If you’re not sure which one you’re dealing with, a proper exam is the fastest way to stop guessing. Book your initial evaluation or call (408) 641-0739. If getting in the car is the hard part right now, ask about a mobile visit and we’ll come to you.
Written by Dr. Orr Soffer, DC, chiropractor at The ChiropractOrr in Campbell, CA. This article is educational and not a substitute for an individual medical evaluation.
