Home / Conditions / Piriformis syndrome
The piriformis is a muscle deep in the buttock, and the sciatic nerve runs just beneath it. When the muscle tightens it can irritate the nerve, causing deep buttock pain that sometimes spreads down the leg. It is less common than it is often said to be, so the first job is making sure the pain is not coming from the spine.
Piriformis muscle pain and pain from a trapped nerve in the lower back can feel very alike, and the spine is by far the more common cause. No scan shows piriformis syndrome directly, so the diagnosis rests on finding the signs that point to the muscle — and not finding the ones that point to the spine.
| Points to the piriformis | Points to the spine | |
|---|---|---|
| Where it hurts | Deep in the buttock, usually one side | The low back, spreading into the buttock and leg |
| Back pain | Little or none | Usually present at some point |
| What makes it worse | Sitting, especially on a hard seat; climbing stairs | Bending, lifting, coughing or sneezing |
| Numbness or tingling | If any, vague and patchy | Follows a nerve's path into the foot |
| Strength and reflexes | Normal | Can be weakened or reduced |
| Pressing the buttock | A deep, tender spot reproduces the pain | Often makes little difference |
Some symptoms mean a nerve in the spine is badly compressed — not the piriformis. Numbness around the groin, buttocks or inner thighs, a change in bladder or bowel control, or weakness in both legs needs assessing the same day. Call the clinic and come in; if we are closed, go to an emergency department.
The piriformis runs from the base of the spine to the top of the thigh bone, and helps turn the hip outwards. The sciatic nerve — the large nerve to the back of the leg — passes just beneath it on its way down, and in some people runs straight through it.
What a picture cannot show is why sitting hurts so much. Sitting presses the muscle directly against the nerve, which is why a long drive or a hard chair brings it on, and why standing up often eases it.
It also explains why the diagnosis is made carefully. The same nerve can be squeezed much higher up, where it leaves the spine, and that is far more common. Treating the buttock muscle when the problem is a disc in the back would miss the real cause.
Most people improve without an injection or surgery. Treatment works on two things at once: easing the pressure on the muscle, and making the muscles around the hip stronger and more flexible.
Break up long spells of sitting, use a cushioned seat, and take your wallet out of your back pocket. Avoid sitting with one leg crossed over the other for long periods. These simple changes often ease the pain noticeably on their own.
Regular stretches for the piriformis and the hip, together with exercises to strengthen the buttock and hip muscles, are the core of treatment. It usually takes several weeks of doing them consistently to see the full benefit.
A local anaesthetic, sometimes with a steroid, can be injected into the muscle, guided by ultrasound and arranged with the radiology clinic we work with. It does two jobs: it eases the pain, and if the pain goes, it confirms the piriformis was the source — which is useful where the diagnosis is uncertain.
Releasing the muscle surgically is uncommon, kept for the few people with a clear diagnosis whose pain persists despite a full course of exercise and an injection.
Not quite. Sciatica describes pain along the sciatic nerve, and most of it comes from the nerve being squeezed where it leaves the spine. Piriformis syndrome is one less common cause, where the nerve is irritated lower down, in the buttock.
Sitting presses the piriformis against the sciatic nerve beneath it. A hard seat, a long drive or something in your back pocket adds to that pressure, which is why standing up or shifting position often eases the pain.
It can add to it. Sitting on a thick wallet presses on the buttock over the muscle and nerve for hours at a time. Moving it to a front pocket is one of the simplest changes to try.
Usually not. Scans are mainly used to rule out a problem in the spine, such as a slipped disc, that can cause the same symptoms. The diagnosis comes from the examination and, sometimes, from how the pain responds to an injection.
Many people notice improvement within a few weeks of changing how they sit and starting the right exercises, though it can take a couple of months to settle fully. Keeping the exercises going helps stop it coming back.
No. Bring any scans of your back or hip, and be ready to describe how sitting affects the pain.
Sciatica · Sacroiliac joint pain · Hip pain · Lower back pain · Nerve or bone?
Be ready to describe what sitting does to the pain. It is often the clearest clue to where it is coming from.
