What Is the Psoas Major?

Psoas major muscles are long muscles located on both sides of the lumbar spine. Most of them are located in the ditch between the lumbar vertebra and the transverse process. The middle section is thicker and resembles a spindle-shaped muscle.

Psoas major muscles are long muscles located on both sides of the lumbar spine. Most of them are located in the ditch between the lumbar vertebra and the transverse process. The middle section is thicker and resembles a spindle-shaped muscle.

Chinese name

Psoas major

Foreign name

Psoas major muscle

Location

Lateral lumbar vertebrae, in front of lumbar vertebra process

Alias

Great lumbar muscle

Psoas major anatomy and function

1. From the side of the 12th thoracic vertebra, 1 to 5 lumbar vertebra and intervertebral disc, and the front and lower edges of all lumbar vertebra processes. The muscle bundles are combined with the diaphragm muscles to form a tendon, which passes through the muscle cavity of the inguinal ligament, descends along the front of the sacroiliac bulge and the front medial side of the hip joint capsule, and stops at the femoral trochanter.

2. The psoas major is located in the ditch between the T12-L4 vertebra and the transverse process. The upper muscle fibers can extend to the lower part of the posterior mediastinum and to the rear of the diaphragm. Most of the psoas major muscles are connected at the edge of the T12-L4 vertebral body and the edge of the intervertebral disc in the form of teeth. The lateral part is connected to the transverse process of the T12-L4 lumbar vertebrae. , Stop at the femoral trochanter inside the thigh root. The median sagittal plane is 40-63mm in distance from the outer edge of the psoas major muscle. The L3 transverse process is the longest. The transverse diameter of the abdominal muscle is the widest and it is the most concentrated part of psoas muscle fibers. The T12-L4 intervertebral foramen is located behind the muscle attachment site, and in front of the transverse process of the lumbar vertebra, and the lumbar spinal nerve is emitted from it.

3. When nearly fixed, this muscle contracts, allowing the thigh to flex and rotate externally. When distantly fixed, one side contracts, causing the trunk to flex to the same side, and the muscles on both sides contract, flexing the lumbar spine and making the trunk forward.

4, function and exercise: The psoas muscle and the diaphragm are collectively called the sacroiliac muscle. The iliopsoas plays an important role in the forward swing of the thighs. Often, auxiliary kicks such as positive kicks, high-legged running, overhanging legs, and sit-ups are used to develop the strength of the psoas muscle. The psoas major is dominated by the muscular branches (T ₁₂ L ₄ ) of the lumbar plexus.

Psoas major clinical

1. The waist bones and muscles have the important functions of maintaining a stable body posture, transmitting the strength of the upper and lower limbs, and completing various technical actions. Once the waist is damaged, it will affect people's daily life and work. The psoas muscle is generally considered to be an important muscle for hip flexion. When the spine is out of balance, the psoas muscle shape will also change. When one side of the psoas muscle is injured or paralyzed, it will cause scoliosis of the lumbar spine; while the two sides of the psoas muscle will be injured and paralyzed at the same time, it will cause the lumbar spine to kyphosis. When there are various kinds of low back pain caused by psoas muscle injury, traditional Chinese medicine massage, acupuncture, hot compress and other treatments are used clinically, and the effect is ideal.

2. Clinically, it is considered that lumbar spinal imbalance is the main factor causing lumbar disc degeneration or even protrusion. The vertical psoas major muscle provides stability to the spinal vertebrae, while the asymmetry of the bilateral psoas major muscles will weaken the lumbar support system or cause uneven force, which will increase the shear force on the disc. This may be One of the important anatomical factors causing lumbar disc herniation. It is now generally believed that after the lumbar disc herniation can cause the ipsilateral psoas muscle activity to decrease and cause it to shrink and shrink.

3. Lumbar disc herniation is a common clinical disease, which is closely related to psoas muscle injury. The psoas major is one of the important paraspinal muscles, in addition to flexing the hip, it also has a movement and stabilization effect on the spinal pelvis. Separate psoas major injury can be seen clinically, but the more common is the compensation and decompensation caused by the interaction with spinal disease. In treatment, using massage, acupuncture, moxibustion, hot compress or other physical therapy, adjusting the psoas muscle can change the abnormal stress at the front of the spine, adjust the mechanical balance of the lumbar spine, and adjust the curvature of the lumbar spine to treat lumbar disc herniation. The psoas major is part of the spine-pelvic-hip joint composite structure, and its complex structure is important. Therefore, more systematic research is still needed to promote the solution of clinical-related problems.

Psoas major other

Spontaneous psoas major hematoma is not common in clinical practice, and is more common in patients with hemophilia and oral anticoagulants. However, femoral nerve injury due to giant psoas major hematoma is very rare. The clinical manifestations of patients with psoas major hematoma are very diverse, including low back pain or pain in the groin area, worsening after walking, radiation pain involving the nerve root distribution area, or persistent chronic blood loss. Physical examination of patients with acute hematoma shows that there is pain around the hip joint on the affected side, limited mobility, and a straight leg elevation test is positive. Patients with chronic hematoma can see swelling in the groin area, reduced skin sensation in the area of the compressed nerve, and even decreased muscle strength. . However, the above-mentioned clinical signs lack specificity, which can be seen in a variety of lumbar spine diseases such as lumbar disc herniation, lumbar spinal stenosis, lumbar tuberculosis, infection, tumors, etc. Therefore, the diagnosis and treatment of psoas muscle hematoma are relatively limited by clinical signs.