The Quadratus Lumborum is actually a very deep abdominal muscle that affects the lower back region. From the backside, it lies beneath some other major muscle of the back, such as the Latissimus Dorsi, the Trapezius, and the Erector Spinae Group. Like its name suggests, the QL is the shape of an irregular quadrilateral. It is fairly small in comparison to the other major back muscles. It connects the pelvis to the lower ribs by attaching along the top of the pelvic/hip bone and the lowest, 12th rib (the floating rib) and along the sides of the lumbar vertebrae. This forms the quadrilateral shape.
The purpose of the Quadratus Lumborum is to stabilize the lumbar spine, hike the hip while walking, laterally flexes to the same side, and extend the back when bilaterally contracting. It also helps fix the 12th rib in place and assists the diaphragm during inhalation. When the Quadratus Lumborum is overworked or strained due to overuse or for compensating for weaker muscles to support the spine and hips, it can cause lower back pain that may even radiate down into the sacrum and gluteal muscles.
Here are some common causes of pain for the Quadratus Lumborum:
- Sitting too long – which contracts the QL, leading to muscle fatigue.
- Poor posture – slouching or leaning to one side for a length of time adds stress to the QL
- Weak muscles – the other surrounding muscles, such as the Lats, Traps, or the ESGs are weak and the QL steps in to help stabilize the spine.
- Unequal leg length – if one leg is physically longer than the other, this causes the hips to be misaligned and causing an unbalance in the QLs.
- Frequently carrying items on one hip – holding a baby or child on the same hip all the time or carrying heavy loads with one hip hiking up to support the item being held can cause the same side QL to get stuck in the shortened position.
In most cases, the lower back pain from the Quadratus Lumborum is not chronic. Adjusting your posture and movements will usually help prevent the QLs from feeling tight and painful. Remember to take frequent breaks from prolonged sitting, use a lumbar support in your chair and in the car, and make sure when you lift heavy items that you bend at the knees rather than at the waist to reduce strain on the lower back. Incorporating lower back stretches, yoga poses, and getting regular massage therapy are all very beneficial in helping to relax the Quadratus Lumborum. As well as focusing on strengthening the surrounding back muscles to reduce the suggestion of the QL needing to step in to compensate for the weaker muscles. When the pain is acute and spasming, resting and icing the lower back is always a good idea. Later you can add heat to help warm up and loosen the tightened muscles.
Remember to take care of your back. Low back pain is no fun and, in the case of the Quadratus Lumborum, it is usually preventable. The QL may be small in comparison to the other major muscles, but it is a big player in your everyday movements.