He came in with a visible tilt to the right and a sore low back. From his posture and his report of diffuse pain in the right lumbar area that was worse with walking and standing and went away when seated and laying down I suspected the quadratus lumborum muscle.
The quadratus lumborum is a thin sheet like muscle that lives between the iliac crest and the 12th rib. It also attaches to the transverse processes of the lumbar spine (L1-L4). Its actions are lateral flexion of the trunk, extension of the spine (if both engage) and stabilization of the trunk. It is at work when we walk and stand keeping our low back aligned. If one side is habitually contracted it can lead to lumbar scoliosis and /or “hip hike” when one side of the pelvis is higher than the other. It is often involved in low back pain and can be overlooked.
If you want to experience this muscle find a comfortable seat with your sitz bones planted on a chair with a hard surface. Sink your thumb into the soft area between your ribs and your pelvis. Use the top of your pelvis as a guide and now gently press toward the spine until you bump up against a thick band of muscle. That thick band is the erector spinea group. The pad of your thumb is now resting on the QL. Keeping your thumb there, gently begin to lift that hip off the chair. You will feel the muscle engage under your thumb. Welcome to the QL! Now feel the other side. Are they the same?
Going back to our friend who came in with the sidebend to the right and low back pain. In the session we found a very tight QL with trigger points that referred pain into his hip. With specific attention to the QL and facial balancing of the low back and pelvis, our friend left walking taller in the world and with much less pain.