The quadratus lumborum, or QL as it is often called, is located in the middle of the lower back. It starts at the at the pelvis (iliac crest) and joins up at the ribs and vertebrae of the lumbar spine. Its main function is to help your torso bend sideways, but it also fixes the 12th rib and aids in expiration of the lungs.
In my experience as a massage therapist, it is one of the main causes of lower back pain in those who sit for long periods of time, such as desk workers and drivers.
When treating QL I generally use some myofascial release, including dry needling, which I find very effective on this muscle. I might also use some deep tissue massage and trigger point therapy if the client is receptive to it. Manual myofascial release techniques might include some compression to the muscle while the patient is lying on their side. All other massage and needling requires the patient to be lying face down.
Taking care of QL can mean a lot of relief from lower back pain.
Firstly, if possible, reducing the number of sitting hours will help. Getting up from your desk at regular intervals, to move around and stretch. Even considering a standing work station can help back pain dramatically.
Because of it’s deep nature, stretches to the QL can be awkward, but not impossible. A sideways bend of the waist will stretch the QL. It’s best to try and create as much space as you can between the pelvis and the lower ribs. For example, crossing one foot over the other and with arms raised, bend sideways to create and arch of the entire body. Use a door frame to stabalise your balance.
Another way to help relieve lower back pain from sitting all day is to stretch through the thorax (midback) to take any pressure off the lower back. A simple way to do this is to lie with a bolster or foam roller along the spine. Support your head and let your arm either rest by your side or stretch outwards. 10 minutes of meditation in this position will help release the days compression of the spine.