Stabilizing the Sacroiliac Joint: The Piriformis Muscle in Yoga

If a picture’s worth a thousand words, then what is an animated video worth? In this yoga blog post we look beneath the skin to see what happens with the piriformis muscle in Reverse Pigeon Pose and provide an overview of the muscle, its attachments and action, and its role in stabilizing the sacroiliac joint. We also examine the use of joint rhythm to optimize the stretch. 

The piriformis muscle originates on the anterior (front) surface of the sacrum and inserts onto the greater trochanter of the femur (thigh bone). Figures 1 (a) and 1 (b) are front and back views of the piriformis muscle. Figure 1 (c) illustrates the stout ligamentous stabilizers of the sacroiliac joint. 

piriformis origin insertion

(Figures 1 (a) is a front view of the piriformis, (b) is a back view and (c) illustrates the ligaments that stabilize the sacroiliac joint. )

Note that the piriformis is a muscular stabilizer of the sacroiliac joint. Imbalances between the piriformis muscles can contribute to subtle asymmetries within the pelvis, which can then be transmitted to the vertebral column. This underscores the importance of achieving a balanced stretch between the two sides when working with this muscle in yoga.

The Biomechanics of Reverse Pigeon Pose

To understand why Reverse Pigeon Pose works to stretch the piriformis we need to know that the actions of this particular muscle vary according to the position of the hip joint. For example, when the hip is in a neutral position, the piriformis acts to externally rotate (turn outward), flex and abduct the hip joint. When the hip is flexed beyond about 60 degrees the piriformis becomes an internal rotator and extensor (and remains an abductor). Muscles stretch when we move a joint in the opposite direction of the action of the muscle. In Reverse Pigeon Pose, the hip is flexed and externally rotated, thus stretching the muscle (which extends and internally rotates the hip in this position). This video illustrates the stretch.

When viewing the video, note how flattening the back moves the origin of the piriformis on the sacrum further away from its insertion on the femur, thus accentuating and refining the stretch. This is an example of lumbar-pelvic and femoral-pelvic rhythm. The last section of the video, where we have digitally hidden one half of the pelvis to expose the movement of the sacrum, illustrates this concept.

piriformis stretch variations

                                        ( Figure 2: variations for stretching the piriformis muscle.)


Figure 2 illustrates some variations for this stretch. Figure 2 (a) is the classic stretch that is typically utilized in yoga. Figure 2 (b) is a modification for persons that cannot practice the full stretch. This variation is also useful to experience the effect of flattening the lumbar in the pose. Figure 2 (c) stretches the piriformis of the lower side leg by adducting and internally rotating the femur. Figure 2 (d) adducts (draws toward the midline) the upper side leg, thus opposing the action of the piriformis for abducting the femur. Figure 2 (e) illustrates a variation commonly employed in physical therapy as part of the regimen for Piriformis Syndrome, a condition that can cause sciatica. In this variation, the upper leg crosses all the way over, thus adducting the femur and stretching the muscle. This is a good alternative for those who experience knee issues in the classic stretch.

I typically do several 20-30 second stretches on each side, easing into and out of the pose. If you experience pain in this (or any) stretch, carefully come out of the pose. Folks with sciatic-type pain should consult a health care practitioner who is appropriately trained and qualified to diagnose and manage such conditions. Follow their guidance, working with yoga as an adjunct in prevention and treatment (where appropriate).

Read more about the Piriformis Muscle in this article from YogaUOnline and Olga Kabel: 3 Types of Pain in the Butt (and What You Can Do About Them).

Study online with YogaU and Julie Gudmestad-Keys to Alignment in Yoga Postures: Befriending Piriformis & Friends.

Reprinted with permission from

YogaUOnline contributor Ray Long MD Author, Ray Long MD, FRCSC is a board certified orthopedic surgeon and the founder of Bandha Yoga. Ray graduated from The University of Michigan Medical School with post-graduate training at Cornell University, McGill University, The University of Montreal and Florida Orthopedic Institute. He has studied hatha yoga for over twenty years, training extensively with B.K.S. Iyengar and other leading yoga masters.                 


YogaUOnline contributor Chris Macivor

3d Graphic Designer / Illustrator Chris Macivor has been involved in the field of digital content creation for well over ten years. He is a graduate of Etobicoke School of the Arts, Sheridan College and Seneca College. Chris considers himself to be equally artististic and technical in nature. As such his work has spanned many genres from film and television to videogames and underwater imagery.         


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