The Tiny Muscle That Can Be a Pain in Your Butt, Back and Knees

Deep within your glutes, there’s a muscle that can cause more trouble than you’d ever think possible. It’s your piriformis muscle. Situated behind the hip socket on each side of your body, it helps rotate and flex your legs while walking, balancing and doing pretty much anything else that involves your lower body.

When it flares up, either on one or both sides, it’s a pain in the butt — and potentially in the back, hip, leg and knee too.

“The piriformis is one of those muscles that people don’t know much about, but greatly affects our everyday lives,” says chiropractor Alex Tauberg, D.C., of Tauberg Chiropractic & Rehabilitation in Pittsburgh.

Just Sore or Something More?

Despite its size and relative anonymity, the pirifomis can cause a whole host of issues. Since it sits on top of the sciatic nerve, it can trigger pain both through repetitive movement — climbing stairs or running — and through sedentary behavior like sitting, which compresses the piriformis into the nerve. Ouch!

That can lead to piriformis syndrome. Your first indication might be a tingling, burning or numbness deep within your glute muscles. It probably won’t be easy to identify the exact source of the pain, but you’ll most likely feel it in your pelvic region, including in your lower back and hips. Although there’s a piriformis muscle on both sides of your body, you’ll probably only feel it on one side.

Even though piriformis problems can arise both when you’re overly active or overly sedentary, the former is an indication of weak hip-stability muscles that causes the piriformis to work overtime. So slow your roll and give your body time to recover (see below for some stretches and other solutions).

The Problem With Pinpointing the Piriformis

The trickiest part of all this is that symptoms of piriformis syndrome aren’t exclusive to that particular problem. That means it’s not always easy to know when it’s a piriformis issue versus another problematic body part. For example, a herniated disc could be the cause of sciatic nerve pressure that’s affecting your lower back and the back side of your leg.

“The problem is that [piriformis syndrome] is a hard diagnosis to actually definitively make, and therefore is usually a diagnosis of exclusion,” says Barbara Bergin, M.D., board-certified orthopedic surgeon at Texas Orthopedics, Sports and Rehabilitation Specialists in Austin, Texas.

However, you can perform a couple of tests that will indicate that it’s likely the piriformis muscle causing the problem. Try these two:

• Resistance Test: Sit down on a chair and use a partner or a rope to apply resistance to the outside of your knees. Try to push your knees out against that resistance. If you feel pain in the gluteal region, it’s likely the piriformis muscle aching.
• Stretch Test: Lie on your side on a bench with the leg on the affected side stacked on top of the other leg. Position your leg so the knee is partially bent and your top calf muscle is resting on the bottom leg’s knee. The knee of the affected side should stick out beyond the edge of the bench. Ask a partner to press down on the affected knee and you might feel the pain of the piriformis muscle along the edge of the buttocks.

Work (and Stretch) It Out

It’s hard to get at the piriformis muscles, but one stretch is sure to target the affected area. Teresa Pierce, PT, of Physio at the Hammond Centre of Macon, Georgia, recommends these two variations:

1. Lie on your back and pull one knee across your chest toward the opposite shoulder. Hold that position, feeling the stretch in your glutes. Release and repeat on the other side. 
   
2. If you prefer to sit, she says, perform a similar version in a chair by crossing one leg over the other and pulling your foot toward your upper thigh. Bend slightly over your knee to feel that same stretch.
   

Stretching will release some of the pain, but you’ll also want to strengthen the region, developing muscles that will support the function of the piriformis. Because of the location of the muscle, “you can’t spot-train it like you can your biceps,” Pierce says. “You need to strengthen the whole area.” Focus on good posture while you exercise, she adds, using your legs rather than your lower back and hips to lift.

Read more: How to Relieve Tension in Your Hips, Back, Neck and More

How to Soothe the Pain

Though fixing the problem is at the top of your list, it might take awhile to get it under control. In the meantime, take measures to reduce any pain the piriformis muscles might be causing.

• Before exercising, warm up properly and thoroughly. When you’re increasing the intensity of your exercising — such as when training for a long race — do so gradually. The rule of thumb: Up your mileage (whether in walking, running or biking) by just 10 percent every week to avoid injury. Take it a little easier by avoiding hills and running or biking on flat surfaces for a bit.
• Add massage to your routine, whether it’s self-myofascial release via the pressure of a foam roller or, even better, a tennis ball (perfectly shaped to put pressure on the piriformis). Or schedule an appointment for a deep-tissue massage.
• Stand more often, whether it’s just taking a short break every hour or investing in a standing desk. The goal is to relieve compression of the muscle on the sciatic nerve. You can also experiment with different chairs or sitting surfaces to see if something new reduces muscle irritation.