Where the piriformis sits
The piriformis is a small flat muscle deep in the buttock, behind the much larger gluteus maximus. It runs from the front of the sacrum, the triangular bone at the base of your spine, across to the top of the greater trochanter, the bony lump you can feel on the outside of your hip. Its job is to rotate the thigh outwards and to hold the pelvis steady whenever you are on one leg, which covers walking, running and every change of direction you make.
What makes it matter clinically is what it sits next to. The sciatic nerve, the largest nerve in the body, leaves the pelvis through the greater sciatic foramen and in most people passes directly underneath the piriformis before running down the back of the thigh. In a smaller number of people some or all of that nerve goes through the muscle belly instead, and that variant may make nerve irritation more likely.
What piriformis syndrome actually is
Piriformis syndrome is the piriformis irritating, compressing or trapping the sciatic nerve. When the muscle goes tight, gets inflamed or spasms, it presses on the nerve, and you get pain in the buttock plus symptoms running down the back of the leg that look almost identical to sciatica from a herniated disc in the lower back.
The difference is where the nerve is being squashed. True lumbar sciatica is compression at the spine, usually a bulging or herniated disc, while piriformis syndrome is compression in the buttock by the muscle itself, and the distinction matters because the two get treated differently.
How it develops in rugby players
A few things about the game feed it:
- Sprinting and cutting. The piriformis works hard through acceleration and deceleration to keep the hip and pelvis steady, so a block of heavy speed and agility work will overload it and leave it tight, fatigued and prone to spasm.
- A blow to the buttock. Take a knee, a boot or the ground on the glute in a tackle or a fall and the muscle bruises and swells, and once it swells it presses on the nerve underneath it.
- Sitting for hours after training. Sitting presses the piriformis onto the sciatic nerve, so if you drive an hour each way to the club or sit through a video session straight after a hard one, you are working on a muscle that is already irritated.
- Loading one side more than the other. Kicking off your dominant leg, passing off one side, turning the same way every time: the hip rotators on that side do more of the work, and one piriformis ends up tighter and thicker than its opposite number.
- Weak glutes. When the gluteus maximus and gluteus medius are weak or slow to switch on, the piriformis gets recruited to cover for them through hip extension and stabilising, and that borrowed work leaves it fatigued, hypertrophied and tight.
What it feels like
The pattern tends to go like this:
- A deep ache in one buttock, dull rather than sharp, and sitting well below the surface behind the big gluteal muscles rather than in them.
- Pain running down the back of the thigh, following the sciatic nerve, and when it is bad it reaches the calf and the foot, which is exactly what lumbar sciatica does.
- Sitting makes it worse, hard chairs most of all, because that presses the piriformis straight onto the nerve. Long drives, team meetings and lectures are the ones players complain about.
- Walking or standing takes the edge off, because getting up and moving lifts the compression and the symptoms usually ease.
- Turning the hip inwards or crossing the affected leg over the other knee brings it straight back, since both of those load the muscle.
- It can start clean on a run and then arrive at a certain distance or time in, as the piriformis fatigues and tightens.
Working out whether it is the piriformis
Piriformis syndrome is a clinical diagnosis, which means it comes from your history and a physical examination rather than one definitive test. A doctor or physiotherapist will check:
- Tenderness. Pressing deep into the buttock over the piriformis reproduces the pain you came in with.
- The FAIR test, for flexion, adduction and internal rotation. Your hip is bent to 60 degrees, drawn across your body and rotated inwards, which pulls the piriformis over the sciatic nerve, and if that brings back the buttock and leg symptoms it is positive.
- Pace sign, where you sit and push your knees apart against resistance. That contracts the piriformis and can reproduce the symptoms.
- The Freiberg sign works the other way round. Forced internal rotation of the extended hip stretches the muscle, and again, symptoms coming back is the positive result.
- A lumbar spine examination. Full spinal range of motion with no radicular symptoms, a negative straight leg raise and no neurological deficit in the legs all point away from the disc and towards the piriformis.
What fixes it
Treatment is conservative, and it splits four ways:
- Stretch the muscle, and the seated figure-4 is the one you can do anywhere: cross the sore ankle over the opposite knee and lean forward. Hold it 30 seconds, three or four times, two or three times a day. The version on your back, ankle over the opposite knee and the bottom knee pulled towards your chest, gets you to the same place.
- Manual therapy from a physiotherapist, meaning deep tissue work over the piriformis, trigger point release with sustained pressure on the tender spots inside the muscle, and dry needling when the spasm has been there a long time.
- Hip strengthening takes the compensating load off. Clamshells, side-lying hip abduction, single-leg bridges and banded lateral walks build the gluteus maximus and gluteus medius so the piriformis stops covering for them.
- Then there is what you stop doing. If sitting is what sets it off, use a cushion, stand for part of the team meeting, break up the long drives and keep your legs uncrossed. If running is what sets it off, drop the sprint volume for now and move the conditioning onto a bike or into the pool.
Neural glides (nerve flossing)
Neural glides get the sciatic nerve moving properly through the tissue around it and bring its sensitivity down:
- The sciatic nerve slider. Sit on the edge of a chair, slowly straighten the sore leg and look up at the same time, then bend the knee back as you look down. That slides the nerve, lengthening it at one end while it shortens at the other. Ten to fifteen repetitions, two or three times a day, slow and gentle. It is not a stretch and it should not feel like one.
- Lying version. On your back with the affected hip and knee both bent to 90 degrees, straighten the knee towards the ceiling until you feel a gentle pull in the back of the thigh, hold two or three seconds, then bend it back. Ten to fifteen times.
When to see a doctor
Most cases settle within four to eight weeks of doing the conservative work consistently. See a sports medicine doctor if:
- It is still there after six to eight weeks of consistent stretching, strengthening and backing off what provokes it.
- The pain is bad enough to keep you out of training and matches.
- Weakness in the leg shows up, or what was already there gets worse.
- Numbness or tingling is significant and does not clear between episodes.
A doctor may request an MRI to rule out lumbar disc pathology and to look at the piriformis itself for asymmetric enlargement, inflammation, or one of the anatomical variants of the sciatic nerve. There is also injection therapy, a corticosteroid or local anaesthetic put into the muscle under ultrasound guidance, and it does two jobs: if the injection settles the symptoms, that points at the piriformis as the source, and it can settle them for a while as well.
Return to rugby
Rugby does not usually have to stop for this. Unless the symptoms are severe you keep training in a modified form while you treat it, and you go back to everything when:
- No pain running, sprinting or changing direction, during or afterwards.
- You can sit for 30 minutes without it starting up, which is a team meeting or the bus to an away game.
- Full hip range of motion with no pain on clinical testing, so a negative FAIR test, Pace sign and Freiberg sign.
- You get through a whole training session and nothing flares afterwards.