I’m developing a new course with my colleague, Tracy Firsching, entitled Stabilizing the Core & the SI Joint – A Manual Therapy Approach. The longer I am in this wondrous field of bodywork I am convinced that leveling the sacral base and pelvis is crucial for addressing all kinds of misalignements in the body. Here’s some interesting facts about the sacroiliac joint (SIJ):
Each SI joint is comprised of irregular, articulating bony surfaces on the sacrum and ilium. They fit together like mirror images of a 3D puzzle. This provides stability, strength and restricts movement so that the considerable weight of the spinal column can transfer to the lower body. It also acts as a shock absorber. These surfaces lock into place during the push-off phase during walking to increase joint stability. The SIJ only slides 2-4mm and rotates 1-2 degrees via ligament stretching during weight bearing and forward bending. Movements are a combination of sliding, tilting and rotation. Although normal SIJ movement is small, it is essential for normal pain-free low back and pelvis function. A loss of this movement is common in people with low back and pelvic pain. Twenty-five percent of low back and pelvic pain involves SIJ dysfunction.
There are two forces that help to “lock” the SIJ: Form closure and force closure. Form closure relates to the form of the bones and how they cleverly fit together to create stability. Force closure is stabilization that result from myofascial contraction. The SIJ has NO muscles passing over the joint. Force closure is from muscles increasing tension on the ligaments. In other words it’s an additional system generated by the contractive action of core myofascial units such as the transverse abdominus, multifidi and thoracolumbar fascia/latissimus dorsi (opposite side), hamstrings and gluteus maximus (same side).
When the sacrum rocks forward into nutation, the ligaments around the SIJ and the muscles provide greater stability by force closure pulling the SIJ together. They also increase FORM closure by increasing tension on the ligaments.
Stay tuned for updates about this seminar!