One of the most common muscles that many massage therapists see causing low-back pain issues is the quadratus lumborum (or QL, as it’s commonly abbreviated). This fairly small, but powerful muscle has its origin at the anterior border of the iliac crest and its insertions on the inferior border of the 12th rib and the transverse processes of the L1-L4 vertebrae. In layman’s terms, it extends from the top rear of your hip bone up to the bottom of your first floating rib and over just next to your spine, as can be seen in the image below.
The quadratus lumborum has several important functions. First of all, it is an important core postural muscle, helping maintain stability for the midsection of the body. When the muscles contract bilaterally (at the same time), they are responsible for helping you straighten up from a bent-over position. If each muscle contracts separately, they are responsible for lateral flexion of the vertebral column (i.e. bending from side-to-side), as pictured below. As you can see, the left quadratus lumborum is being stretched whereas the right one is being contracted to provide the right lateral flexion of the torso.
So why is it that the quadratus lumborum is so frequently a cause of low back pain? One key reason has to do with the muscles sitting directly on top of them: the erector spinae. The erectors, which extend from the top of the iliac crest all the way up the back to the base of the skull, are also core postural muscles primarily responsible for keeping the spine straight as well as straightening it from a bent-over position. However, most people – especially those who work at computers or sit for long periods of time – have erectors that are weak or overstretched due to all-too-common bad desk posture. When you sit at a desk and aren’t keen on paying attention to your posture, it is very common for the shoulders to slope forwards and the entire back to curve.
This poor posture overstretches and weakens both the erector spinae as well as the quadratus lumborum while concurrently overtightening their antagonists in the front of the body such as the abdominals and psoas. (More on those in later blog posts!) With the erectors weakened, the quadratus lumborum usually ends up picking up the slack, as it were, and attempts to do more work than it can handle, causing the muscle to strain. Hence, when someone attempts to straighten up from being bent over, they may feel that unpleasant twinge or spasm in their low back which signals that the quadratus lumborum has just strained itself. This is also why people who do not use their legs to lift heavy items end up with lower back muscle strains from bending over and attempting to use their low backs to lift.
The quadratus lumborum muscles are also a few layers deep, sitting below both the latissimus dorsi as well as the erector spinae. This can make it a challenge to effectively work on the quadratus lumborum, especially if the other two muscles sitting on top of it are tight as well. Fortunately, there are excellent massage techniques to gradually work through the other muscle layers as well as specific angles at which the belly of the quadratus lumborum is easier to access, meaning that sufferers from low back pain caused by a tight quadratus lumborum do not have to fear that they will suffer from it forever.
Other helpful exercises for the quadratus lumborum include stretching (such as in the picture above showing a side stretch) as well as keeping good posture when working at a computer or in another occupation where sitting for lengthy periods is common. If the issue happens to originate from a misalignment of the lower spine, then a visit to a chiropractor might also be in order. With a little care and forethought to your posture and movement habits, your quadratus lumborum should serve you faithfully for years to come with little, if any, discomfort or pain.