Around thirteen years ago, after recovering from a fractured radius (a long story involving a moped and cobblestone Key West roads), I somehow managed to injure my left hip. Shooting, burning sensations lanced down the back of my left thigh, and finding a comfortable position to do anything was well-nigh impossible. After a visit to my chiropractor, I learned that the piriformis muscle was the culprit. I had been taking yoga classes for several years at this point, but I had never heard of this muscle, and it was making its presence known.
The piriformis is one of the deep-six lateral rotators of the hip joint (along with the superior and inferior gemelli, obturators internus and externus, and quadratus femoris). All of these lateral rotators come in pairs, and for hip health, it is important that they be balanced side to side in both strength and flexibility. To give a bit of anatomical orientation, the piriformis is a pear-shaped muscle that lies underneath the gluteus maximus and is located between the gluteus medius and the superior gemellus. Because it attaches to the front of the sacrum (inside the pelvic bowl) and runs along to the greater trochanter on the outside of the femur, this little muscle overlies the sciatic nerve. In some folks, the sciatic nerve actually runs through the muscle fibers. If one piriformis becomes overtightened (in my case, on the left side), it can pull the sacrum out of alignment and compress the sciatic nerve, mimicking the symptoms of sciatica—a sensation I experienced firsthand.
This little muscle also has other functions besides laterally rotating the hip–it also assists in hip abduction and in medial rotation of the thigh when the thigh is flexed more than 60 degrees (see Joseph Muscolino’s Muscular System Manual, p. 516—many thanks to Laurel Beversdorf to pointing me to this reference). Thus, it is always working behind the scenes whenever we move our hips and thighs.
Because so many of us in Western culture have the habit of externally rotating one or both hips (duck-foot syndrome), the piriformis will often be locked short and be both tight and weak. And this muscle doesn’t work in isolation—through connective tissue and movement relationships up the torso and down the lower limb, an unhappy piriformis can affect not just your hips, but also your pelvic floor, your knees, and your low back. Check back on Friday for a great stretch that can bring hip pain relief and make your piriformis your friend again!