The piriformis muscle is one of a group of deep gluteal muscles that sits underneath the gluteus maximus. It primary functions are to externally rotate the femur (turn the knee outward) and to abduct the hip (to swing your leg in a straight outward motion to the side). Its origin is at the anterior portion of the sacrum, usually S2-S4 and runs along the sacrotuberous ligament, then inserts at the greater head of the trochanter.This muscle can be problematic for many people resulting in a deep ache or tightness within the hip, as well as some referred pain into the side or back of thigh. Usually it is dancers or gymnasts who will experience the most trouble with piriformis as they are required to turn their feet out so much, but considering that the deep gluteal muscles also act as a general stabiliser in our hips they can tighten up quite easily through everyday action.
It is quite easy to palpate piriformis – and indeed work on loosening it yourself- by pressing straight through the centre portion of gluteus maximus until you feel the sore spot. Using a tennis ball pinned between the muscle and the wall at home works quite well.
Interestingly when the hip is flexed to 90 degrees, the muscle changes its action and becomes a medial rotator and pulls the leg inward. This is an important change as this is what allow the classic piriformis stretch to be performed – which is to bend the hip of the affected leg and outwardly rotate. An easy way to achieve this is to sit on a chair, cross the ankle of the affected leg on the opposite knee and while slightly pressing down on the knee of the problem leg lean forward until you feel a stretch.
Another interesting note is that a small percentage of people are born with the sciatic nerve running through the actual muscle instead of laying alongside it. As you can imagine this causes rather strong sciatic pain if the muscle becomes overused.
By Kristen Burgess ~ Remedial Massage Therapist
