The gluteus medius and gluteus maximus in the human body jointly maintain pelvic stability. When there is weakness in the gluteus medius, the contralateral psoas muscle will contract excessively; In addition, unilateral shortening of the quadratus lumborum muscle can cause lower back pain in pelvic life, which can be seen everywhere in patients, and most people show lumbar disc herniation after going to the hospital for X-rays. Actually, according to relevant research, only4% of the population has lower back pain caused by true lumbar disc herniation, while 96%, the vast majority of lower back pain, is caused by other reasons. From our soft tissue perspective, the most common cause of long-term back pain is injury to the quadratus lumborum muscle. And what is the quadratus lumborum muscle? Below, I will explain to everyone:

The quadratus lumborum is an important deep muscle in the lower back, called the quadratus lumborum because it is like a square, connecting the ribs, lumbar spine, and ilium. In fact, the quadratus lumborum is not a single muscle, but can be divided into three bundles according to its fiber shape.

The iliac rib fibers attach almost vertically downwards to the iliac crest and iliopsoas ligament, and connect upwards to the iliac crest and iliopsoas ligament12 ribs.

The iliopsoas fibers pass downwards through the attachment point of the ipsilateral iliac bone and upwards through the upper partFour lumbar transverse processes diagonally pass through and extend to the inner side of the iliac rib fibers. The lumbar rib fibers with the least fiber span downwards across the L2-L4 or L5 transverse processes, attach upwards to the 12th rib, and diagonally pass through and extend to the iliopsoas fibers to form an interwoven structure.

Summary: The iliac rib fibers form a vertical shape and travel from the ilium to the ilium bone12 ribs; The iliopsoas fibers are oblique, running from the ilium to the transverse process of the lumbar spine; The lumbar rib fibers run obliquely from the transverse process of the lumbar spine to the 12 ribs, intersecting with the iliopsoas fibers. So from the perspective of fiber orientation, the quadratus lumborum should be seen as three muscles.

In addition, the iliopsoas ligament we are referring to originates fromImmature lumbar muscle fibers before the age of 20 only exist in animals with an upright posture.

Let's take a look at the function of the quadratus lumborum muscle:

When the unilateral quadratus lumborum muscle contracts, it elongates the contralateral quadratus lumborum muscle and produces ipsilateral flexion; This muscle can also stabilize during inhalation and passive exhalation12 ribs, assisting passive exhalation; Simultaneously contract both lumbar muscles to extend the trunk; The issue of the height of the waist muscles and the contralateral buttocks.

The nerves that innervate the quadratus lumborum are derived from the lumbar plexusSpinal nerve innervation of L1-L4.

Now let's talk about the symptoms of injury to the quadratus lumborum muscle:

From the perspective of pain points, the involvement pain of the quadratus lumborum muscle can cause pain down to the sacroiliac joint and below the buttocks, and sometimes the pain can extend forward along the iliac crest to the lower abdomen, groin, and greater trochanter region of the femur.

Below are the examination methods for the quadratus lumborum muscle:

The patient is standing upright, with feet shoulder width apart and arms placed on both sides. The therapist stands behind the patient, placing their hands on both sides of the patient's buttocks to stabilize the pelvis so that it does not rotate or tilt.

At this point, instruct the patient to slide their hands freely along the outer side of their legs and not rotate their torso.

Observe that the patient's hands can slide down along the outer side of the leg to the same position, which is at the knee joint level.

If there is pain, stiffness, or tension on the opposite side during scoliosis, it usually indicates damage to the quadriceps muscle.

Finally, let's talk about the isometric contraction of the quadratus lumborum muscle- Relaxation exercise:

The patient lies on their side, with their upper leg extended and lower leg bent. Instruct the patient to lift their hip to resist the pulling of their leg. Let it use the muscles of the iliac crest to resist traction and tighten the hip joint towards the shoulder.

Action: The therapist holds the patient's ankle joint above and extends it outwards20 degrees. Advise the patient to resist the action and instruct them not to move for about 5 seconds. Ensure that the patient's body remains neutral and does not rotate forward or backward. After the patient persists for 5 seconds, relax them. When relaxing, pull the leg and stretch the quadratus lumborum muscle. Then repeat this contraction relaxation elongation process multiple times.

We can use the above examinations and exercises to treat the problem of lumbar muscle injury. At the same time, some people have suggested that the third lumbar transverse process syndrome is also related to the lumbar muscle, but it has not been evidence-based. The quadriceps muscle is so easily damaged, so we should pay attention to it