Low back pain usually comes from a disc, a facet joint, the sacroiliac joint or the muscles and fascia. Each has its own pattern. Treatment starts with finding which one is causing the pain.
Low back pain is the most common pain complaint in medicine. It is also the one most often treated by guesswork.
What it is
Most low back pain comes from one of four sources: the discs, the facet joints (small joints at the back of the spine), the sacroiliac joints (where the spine meets the pelvis), or the muscles and fascia (the tissue wrapping the muscles). Each has a pattern we can spot.
A small share has a serious cause: infection, fracture, tumor, or cauda equina compression (pressure on the nerve bundle at the base of the spine). Screening for those is the first job. Mostly we do it by asking questions, not by scanning everyone.
How it usually presents
- Pain across the lower back, sometimes into the buttock.
- Worse with sitting suggests a disc. Worse with standing and leaning back suggests the facet joints.
- Pain below the knee suggests a nerve root is involved. See sciatica.
- Pain on one side just below the belt line is often the sacroiliac joint.
How we treat it
- Find the pain source instead of treating ‘back pain’ as one thing.
- Physical therapy aimed at what is actually failing, not one-size-fits-all core work.
- Epidural injection, facet injection or sacroiliac injection depending on the source.
- Attention to sleep, blood sugar and lost fitness. These are what turn one bout into a chronic problem.
To get checked, call us or request an appointment. If this began with a crash or a fall, see accident and injury care.
What usually gets missed
The sacroiliac joint is the source missed most often. The reason is built in: it looks normal on MRI even when it is causing all of the pain. Somewhere between one in six and one in five cases of chronic low back pain start there. Almost none are found without a targeted injection.
The second common miss is assuming that a disc problem on a scan is the cause. Disc bulges, degeneration (discs breaking down) and even herniations are very common in people with no pain at all. They get much more common with age. Finding one explains nothing on its own.
What to expect over time
Acute low back pain truly goes away on its own in most cases. Most people improve a great deal within six weeks, whatever is done. That number is why early care is deliberately conservative (non-surgical). It is also why that same approach gets wrongly used on people six months in.
Once pain lasts past three months, the picture changes. It becomes much less likely to clear up on its own. Lost fitness starts adding to the pain by itself. Waiting longer stops being watchful and starts being neglect.
When this becomes urgent
Loss of bladder or bowel control, numbness in the saddle area, or leg weakness that is getting worse is a same-day emergency. Cauda equina compression has a surgery window measured in hours. Back pain with fever, or in someone with a history of cancer, IV drug use or recent infection, also needs urgent assessment.
Related: two causes of low back pain that get missed in adults are ankylosing spondylitis and an adult degenerative scoliosis curve.
Common questions
When is back pain an emergency?
Loss of bladder or bowel control, numbness in the saddle area, or leg weakness that keeps getting worse. Those need an emergency room the same day, not an appointment.
The detail is in Sciatica.
Should I rest?
Rest lightly for a short time, then move. Bed rest past a day or two makes results worse.
Living With It — Practical Guides explains what that looks like.
Sources
- Qaseem A et al. Noninvasive Treatments for Acute, Subacute, and Chronic Low Back Pain: A Clinical Practice Guideline From the American College of Physicians. Annals of internal medicine, 2017. PubMed 28192789
- George SZ et al. Interventions for the Management of Acute and Chronic Low Back Pain: Revision 2021. The Journal of orthopaedic and sports physical therapy, 2021. PubMed 34719942
- Apeldoorn AT et al. Management of low back pain and lumbosacral radicular syndrome: the Guideline of the Royal Dutch Society for Physical Therapy (KNGF). European journal of physical and rehabilitation medicine, 2024. PubMed 38407016
- McKenzie BJ et al. Agreement between high-quality clinical practice guidelines in their treatment recommendations for low back pain: a systematic review. The spine journal : official journal of the North American Spine Society, 2025. PubMed 40639620
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