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Where is the piriformis muscle?

The piriformis muscle is the primary lateral rotator, (a muscle that helps move the leg in an outward direction) of the hip. It is the muscle in the middle of your buttocks (from the rim of the sacrum to the top of your outer thigh bone, called the greater trochanter). The sciatic nerve goes over the other five deep rotators, (muscles that allow the hip to rotate) and under the piriformis as it is leaving he sacral plexus and descending the limb.

1. Piriformis Impingement

In some instances the sciatic nerve will come over the top of the piriformis muscles or in 10% of cases actually perforate the muscle. This is much more likely to lead to problems with the sciatic nerve being compressed, called Piriformis impingement. Pain from this condition is felt not only in the back of the leg but down to the calf and sole of ones foot.  There may also be numbness, tingling and a burning sensation.
Treatment consists of stretching and massage therapy, however in this case surgery may be required.

How to assess if you do have an impinged piriformis?

To test for this impingement is lie on your side with the hip and knee of the affected side flexed on the edge of the table so there is room for the leg to drop off the table. Bring the hip into medial rotation, (move the leg towards your body) and if you have a therapist they can use one hand to stabilise the pelvis and the other hand to apply a gentle amount of pressure on the knee to help stretch the piriformis further. The therapist must watch to make sure that the pelvis stays close to vertical and try not to twist the torso. If the pain that you have been feeling is replicated, the pain down the back of your leg then it is most likely the piriformis is impinged.

2. A contracted piriformis

A second condition of the piriformis muscle is associated with the muscle contracting, (shortening) and developing trigger points.  Why?

Climbing stairs, doing squats and even sitting can aggravate the piriformis muscle, especially if ones posture/style is biomechanically unsound. For example, if there is too much external (movement outwards) or internal rotation of the leg when performing these activities. This syndrome can be caused from too much activity or too little. If your job keeps you sitting for long periods of time then you have an excuse to get up and move!!

What can happen as a result of this issue?
Tension in the piriformis can put a twist in the sacroiliac joint, adding to your pain. The resulting tilted sacrum can make you appear to have a short leg. Shortening of the piriformis can make it difficult to move ones leg inwards and outwards. Sitting in one spot for a period of time will be uncomfortable causing you to squirm. A tight piriformis muscle can impinge upon the pudendal nerve, causing impotence in males and pain in the groin, genitals or rectal area of either gender. Piriformis muscles compressing gluteal nerves and blood vessels are believed to be responsible for gluteal muscle atrophy wherein one or both vessels are believed to be responsible for gluteal atrophy where both buttocks can waste away. (Davies 2004)  Hmm…although to some of us ladies this may seem like a good idea there is nothing like a round, firm behind to fit into jeans for shape!

Treatment
Massage applications and stretching aimed at the gluteal muscle and deep rotators. However, your therapist has to be careful over the glut (buttocks) to make sure the pressure does not contact the irritated sciatic nerve.

It is believed by some that ones posture is based on the balance of the piriformis and psoas across the sacroiliac joint. (Myers, 1998) The psoas is the muscle attached to the sides of the vertebrae from your last rib and continuing down to the pelvis and it flexes the thigh and vertebral column.

It is important in treatment to always consider the opposing muscle, the “antagonist” which is in reality the co-worker of the muscles to steady a movement. When one muscle is contracted the opposing muscles are lengthened and weakened.
 

Bibliography

•    Brukner & Khan (2005), Clinical Sports Medicine, McGraw Hill, Australia
•    Davies C (2004), The Trigger Point Therapy Workbook, New Harbinger Publications, USA
•    Liebenson C (1996), Rehabilitation of the Spine-A Practitioners Manual, Williams and Wilkins, USA
•    Lowe W (1997), Functional Assessment in Massage Therapy, OMERI, USA
•    Kapit & Lawrence (2002), The Anatomy Coloring Book, Benjamin Cummings, USA

Articles:

•    Myers Thomas (1998), Body Poise: Psoas-Piriformis Balance, Massage Magazine, p72

Kerrie Baumgartner
Diploma of Remedial Massage
Victoria University
0402 125962
rungirlgo@hotmail.com