The quadratus lumborum (QL for short) is an important muscle to maintain in relationship to spinal health. Inherent in the name is its shape and location – square-like and in the lumbar (low back) region. It is a large flat muscle that attaches to the twelfth rib and L1-L4 in the lumbar spine, making its way down to attach on the posterior iliac crest (the top of the pelvis on the back side) and iliolumbar ligament. It is considered a deep trunk muscle, tucked away deep beneath the erector spinae and in close range of the viscera on the other side, where it protects and cushions the kidneys, and sits in close relationship with the psoas major and the diaphragm.
And wow, does this muscle have a lot of functions! It holds the twelfth rib steady during abdominal breathing. It elevates the hip and participates in lateral flexion of the lumbar spine along with anterior pelvic tilt and lumbar extension. It also assists in rotating the torso. The fibers of the lateral side of the QL are meant to act as a mover of the trunk and/or pelvis and the medial fibers are meant to stabilize the trunk in maintaining good posture.
QL’s everyday partner in crime is the contra lateral (opposite side) gluteus medius – these two muscles work together in a sling to balance each other out during walking. This is particularly relevant in everyday life when we are carrying something heavy (think grocery bag with two gallons of milk in it) in one hand. In this scenario the QL and its opposing gluteus medius have to be awake and in cooperation in order to maintain correct posture and gait. When both of these muscles are weak, the hips and core can’t stabilize the movement pattern and excessive stress often moves downtown and causes distress in the knee (on the glute side).
Overuse or under use of the QL is often considered to be a common source of reccurring lower back, buttock and hip pain. This muscle usually gets called in to do the job of the erector spinae if they are weak or prohibited. The modern seated lifestyle puts QL into constant contraction where it becomes short/tight and can eventually land in spasm. It can also be strained if you have a habit of sitting crossed legged with the same leg on top all of the time. In this scenario, a higher percentage of body weight lands into the bottom leg, and the top leg QL muscle works unnecessarily for as long as the position is held.
If low back pain prevention or easement is the goal, keeping the QL muscles strong and supple is good a place to start. On Friday I’ll post a video of a YTU pose that helps keep your QL in good shape!