Piriformis syndrome is a neuromuscular condition where the piriformis muscle, a small muscle deep in your buttock, compresses or irritates the sciatic nerve. This compression produces pain, tingling, or numbness that can radiate from the buttock down the back of the leg, closely mimicking sciatica caused by a spinal disc problem. Roughly 17% of people with chronic low back pain may actually have piriformis syndrome as the underlying cause.
Where the Piriformis Sits and Why It Matters
The piriformis is a flat, band-like muscle that runs from your lower spine (the sacrum) across to the top of your thighbone. Its job is to help rotate your hip outward and stabilize your pelvis when you walk. The sciatic nerve, the largest nerve in the body, typically passes directly beneath this muscle on its way down the leg.
In about 90% of people, the sciatic nerve travels as a single bundle below the piriformis. But in roughly 13% of the population, the nerve takes an unusual path: it splits around the muscle, passes through it, or runs above it. These anatomical variations don’t guarantee problems, but they may increase vulnerability to compression when the piriformis tightens, swells, or spasms.
What Piriformis Syndrome Feels Like
The hallmark symptom is a deep, persistent ache in one buttock. People describe the sensation as burning, shooting, or tingling, and it frequently radiates down the back of the thigh. In some cases the pain extends into the lower leg, following the path of the sciatic nerve. Numbness in the buttock or along the back of the leg is common as well.
Certain activities and positions tend to make things worse:
- Sitting for long stretches, which directly compresses the piriformis against the nerve. Office workers, long-distance drivers, and cyclists are particularly affected.
- Walking, running, or climbing stairs, all of which engage the piriformis repeatedly.
- Getting out of bed or standing up after sitting, when the muscle transitions from a shortened to a lengthened position.
- Hip movements like crossing your legs or rotating your thigh inward.
The pain is usually one-sided. If both buttocks hurt equally, a different diagnosis is more likely.
What Causes the Muscle to Tighten
There’s rarely a single dramatic event. Most cases develop from repetitive stress or sustained postures. Sitting for hours each day keeps the piriformis in a shortened, compressed state. Runners and people who suddenly increase their activity level can irritate the muscle through overuse. A direct fall onto the buttock, a car accident, or even carrying a thick wallet in a back pocket can set things off. In many cases, no clear trigger is identified, and the muscle simply tightens gradually over weeks or months.
How Piriformis Syndrome Is Diagnosed
There is no single imaging test that definitively confirms piriformis syndrome. MRIs and X-rays are typically used to rule out other causes of sciatic pain, like a herniated disc or spinal stenosis. The diagnosis itself rests heavily on physical examination.
During an exam, a clinician will use specific maneuvers designed to either stretch or contract the piriformis and see whether they reproduce your symptoms. In one test, the examiner forcefully rotates your straightened leg inward, stretching the piriformis. If this recreates your buttock pain, it points toward the diagnosis. In another, you sit and push your knees apart against resistance, which contracts the piriformis. A third involves lying on your side with the painful leg on top and the knee bent, then lifting the knee a few inches off the table and holding it there. Buttock pain during any of these maneuvers adds confidence to the diagnosis.
Because the condition overlaps so much with disc-related sciatica, getting the diagnosis right often means systematically eliminating spinal causes first.
Physical Therapy and Stretching
Most people improve with conservative treatment, and physical therapy is the cornerstone. The goal is to reduce compression on the sciatic nerve by loosening the piriformis and the surrounding tissue.
Stretching is the most accessible starting point. One effective stretch involves lying on your back with both knees bent, crossing the affected leg over the opposite knee, then pulling the bottom knee toward your chest until you feel a deep stretch in the buttock. Holding this for 30 seconds and repeating several times a day can gradually reduce tightness. A variation uses the same crossed-leg position but presses the knee of the affected side toward the floor with the opposite hand, targeting the muscle from a different angle.
Applying heat before stretching helps relax the muscle and makes the stretch more effective. Ice afterward can reduce any irritation that the stretching provoked. This heat-before, ice-after pattern is a simple way to get more out of each session.
Manual therapy techniques add another layer. Myofascial release, where a therapist applies sustained pressure to trigger points in the buttock, reduces spasm and pain. Deep friction massage has been shown to decrease discomfort during daily activities. A technique called neural mobilization specifically targets the sciatic nerve itself, using coordinated joint movements to gently glide or tension the nerve and reduce irritation where it’s compressed.
Injections for Persistent Pain
When physical therapy alone isn’t enough, injections into the piriformis muscle can provide significant relief. Two main types are used.
Corticosteroid injections combine a local anesthetic with an anti-inflammatory steroid, delivered directly into the piriformis under imaging guidance. These can calm inflammation and break the pain-spasm cycle, giving you a window to make more progress with stretching and therapy.
Botulinum toxin injections take a different approach. Instead of reducing inflammation, the toxin partially paralyzes the piriformis, preventing it from spasming and compressing the nerve. In one study, 65% of patients reported at least a 50% reduction in pain. Another found that 77% of patients rated their outcome as “good” or “very good.” Relief typically begins within five to seven days. Some people need a second injection, but many get lasting improvement from one round. The effect of the toxin wears off over several months, but by then the underlying tightness has often resolved.
When Surgery Becomes an Option
Surgery is reserved for the small number of people who don’t respond to months of physical therapy and injections. The procedure involves releasing (cutting) the piriformis muscle to permanently remove pressure from the sciatic nerve.
Results are encouraging for those who reach this stage. In one surgical series, 83% of patients had satisfactory outcomes. Most striking, sciatic pain resolved in the majority of patients within three days of the operation. Pain scores dropped from an average of 9 out of 10 before surgery to 3 out of 10 at the one-year follow-up. Hospital stays averaged about five days, and no significant complications were reported.
Some patients do experience persistent buttock soreness after surgery, even when the sciatic symptoms resolve. In most cases, this residual discomfort fades within the first year.
Daily Habits That Help
Because prolonged sitting is one of the most common aggravators, breaking up long periods of sitting makes a real difference. Standing or walking for a few minutes every 30 to 45 minutes keeps the piriformis from tightening. If you drive for a living, a cushion that reduces pressure on the buttock can help.
Strengthening the muscles around the hip, particularly the glutes and hip abductors, takes workload off the piriformis so it doesn’t have to compensate. Foam rolling the buttock area between therapy sessions can maintain the looseness gained from manual treatment. Paying attention to posture and movement patterns, especially during exercise, helps prevent the spasm cycle from restarting once you’ve gotten it under control.