Spondylolisthesis is when one vertebra, one of the stacked bones of the spine, slides forward over the one below it. It is most common in the lower back, where it is one of many possible causes of lower back pain. It does not always hurt, and some slips are only found on an X-ray taken for an unrelated problem.
Repeated arching in sport can crack a thin bridge of bone and let the vertebra slip
The weak point is the pars interarticularis, a thin strip of bone at the back of the vertebra that connects its upper and lower joints. Stress fractures there are linked to sports that bend the lower back backwards again and again, such as gymnastics and weightlifting, and if the broken bone separates, the vertebra can slide forward. Pain that builds with activity and settles with rest is typical, sometimes with tight hamstrings.
In older adults, worn discs and joints can let a vertebra drift forward
This is the degenerative kind. As discs lose height with age, the ligaments and joints holding each vertebra in place weaken, and one can shift forward on the next. It is more common in women and after the age of 50.
A doctor grades the slip on a side-on X-ray by how far the bone has moved
Doctors use the Meyerding scale, which measures the forward shift against the vertebra below: grade 1 is up to a quarter of its width, grade 2 up to half, grade 3 up to three quarters and grade 4 up to the full width, while grade 5 means the bone has slid completely past it. Cleveland Clinic calls grades 1 and 2 low grade and grades 3 and 4 high grade. An MRI scan shows the nerves, and the NHS says one may be arranged when pain, numbness or weakness reaches the legs.
A slip can crowd the nerves and send symptoms into a leg
A slip often narrows the spinal canal and the openings where nerve roots leave it, which can send pain, numbness or tingling down a leg, the pattern often called sciatica. The degenerative kind is the one usually tied to the narrowing known as spinal stenosis, where standing and walking tend to make symptoms worse and sitting or bending forward eases them.
Decisions about the slipped bone itself belong to a spinal specialist
Care usually starts without an operation. StatPearls calls non-surgical treatment the first-line approach, and the NHS lists avoiding what makes it worse, anti-inflammatory painkillers, steroid injections and physiotherapy. The AAOS says surgery is considered for a high-grade or worsening slip, nerve compression causing pain or weakness, or back pain that has not improved with other treatment, and the NHS names spinal fusion among the operations used.
The Sync works on comfort and movement around a slip and measures the change
Care at The Sync begins with assessment and measurement. SpinalSync tests each segment of the spine on its own and combines the readings, which appear on a screen as they are taken, so measuring again later shows what has changed. MyoSync works with the fascia and soft tissue. With a known slip, that work is aimed at comfort and movement in the back around it.
The Sync does not diagnose, prescribe medication, inject, operate, or provide or read imaging, so the type and grade of a slip come from your doctor, and a Sync specialist says early if anything needs a doctor first. Our back pain page shows how an assessment runs.
Common questions about spondylolisthesis
No. In spondylolisthesis a bone of the spine moves forward, while a slipped disc is disc tissue pushing out between two bones. Both are possible causes of sciatica, and imaging read by a doctor tells them apart.
It can. Growth spurts in children and teenagers raise the risk of the slip progressing, and doctors may repeat X-rays to check whether the vertebra is moving. In adults with a low-grade slip, significant progression is rare.
For most people with a mild slip, MedlinePlus says exercise and changes in activity help, while the NHS advises avoiding activities that make symptoms worse. A young athlete with a recent stress fracture may be told to rest from sport for a time. Your doctor or physiotherapist is the one to say what suits your slip.
A Sync specialist can assess how your back moves, measure it again over time and work on comfort and movement alongside your doctor's advice. The Sync does not diagnose, prescribe medication, inject, operate, or provide or read imaging, so decisions about the slipped bone stay with a spinal specialist.
Written by the Aphyx Content team, reviewed by the clinical team at The Sync. Published 20 October 2026. Last updated 20 October 2026.