This is a series on low back pain. If you missed the summary of causes, go back to Part 1.

Whenever the skeleton is asymmetrical, the muscles are affected. Our bodies want to be in a state of equilibrium and have complicated systems to maintain that internal balance (homeostasis). That applies the musculoskeletal system as well. For example, if one leg is longer than the other, the pelvis tips. In response to that inequality, the muscles and their nerves (neuromuscular system) try to make adjustments to create balance. Since you can’t change the size of the bones, the muscles are always working to make them even. The extra work load adds stress with the result that the muscles eventually use up their energy and nutrient stores and become fatigued and tight. As that happens the muscles become less and less healthy, more dysfunctional and then painful.

Life puts many physical stresses on the muscles of the low back so the extra work caused by asymmetries can be the spark that ignites the pain. Once Trigger Points have developed in muscles, even 1/8 inch difference in the length of the legs can be a perpetuating factor for pain according to the medical text by Travel and Simons, Myofascial Pain and Dysfunction: The Trigger Point Manual. A Trigger Point is an area of hyperactivity and hypersensitivity in soft tissue that refers pain or other sensations away from the site. It takes a while to develop an area of dysfunction, so the increased work load stimulated by an asymmetry can cause or perpetuate a Trigger Point.

Other asymmetries that I look for in my Neuromuscular Therapy center near Boston can lead to pain in the low back: scoliosis (curved spine), hemipelvic asymmetry (the two bones of the pelvis are uneven), Morton’s Foot Structure (long second toe), short upper arms (in proportion to back length).