Piriformis Muscle

The piriformis muscle is a small muscle deep in the buttock area. It attaches at one end to the sacrum or the tailbone, and at the other to the femur - the long thigh bone.

Despite being small the muscle has an important role. Its main action (job) is to turn the hip joint outward, but it only does this when the hip joint is in a neutral position which means not bent up. If the hip joint is bent up then piriformis also moves the leg outwards or away from your midline. The technical term for this is abduction.

You would be using piriformis:

• when you are moving your leg across to get out of a car
  
• when you move across to another seat without standing up

The piriforms muscle is also very important for stabilising the hip joint and the pelvis so it is also in action:

• when you are standing on one leg or turning your trunk
  
• it will also be busy when you are standing on an unstable surface
  
• when you are keeping your balance on a moving train or bus

You can feel the piriformis muscle by feeling along the edge of the sacrum or the tailbone where it is attached. Its worth noting though that this muscle is deep in there and has close relationships with other pelvic muscles - look at the diagram above to see what I mean.

An important point to make about this muscle is that the sciatic nerve either runs through it (in 30% of us) or very close by in the rest of us. This can sometimes lead to misdiagnosis of sciatica caused by bulging discs.

Its a bit difficult to diagnose this problem yourself so you would probably need to be examined by a health care pr19-Apr-2010"piriformis-syndrome-1.html">Piriformis Muscle Hub Page

What is Piriformis Syndrome

Treatment for piriformis problems

Video demonstration of a piriformis stretching exercise

Lower Back Pain Toolkit Home Page

19-Apr-2010