The main symptoms that are easily confused with the disappearance of the shadow of the psoas major muscle are the following, and careful differential diagnosis should be paid attention to. Lumbar muscle spasm: chronic lumbar muscle strain, as a common clinical disease, multiple morbidity, more pathogenic factors, the main symptom is lumbar pain, daytime exertion aggravated, after rest can be reduced, over time, can make the muscle fiber degeneration, and even a small number of tears, the formation of scars or fiber cords or adhesions, leaving long-term chronic low back pain. Non-surgical treatment is the main treatment. If various non-surgical treatments are ineffective, surgical treatment can be performed. Swelling of the psoas major muscle: The psoas major muscle is a long pike shaped muscle that starts from both sides of the lumbar vertebrae and terminates with the iliacusmuscle on the lesser trochanter of the femur, collectively known as the iliopsoas muscle. Swelling of the psoas major muscle is mostly due to inflammation. Pain: Mostly mild dull pain, light at rest, heavy with exertion, aggravated by coughing, sneezing or holding, but the patient can sleep better at night, which is different from malignant tumors. Patients complained that the pain site is sometimes inconsistent with the lesion. Patients with lesions in the thoracolumbar segment often complain of pain in the lumbosacral region. If the patient is not examined carefully, or if only lumbosacral X-ray is taken, the diagnosis is often missed. In severe cases of posterior convexity deformity, it can cause lower back strain and produce pain. If the lesion compresses the spinal cord and nerve roots, the pain may be quite intense and radiates along the nerve roots. Abscess of the psoas major muscle: It is an inflammation of the lumbar or abdominal cavity that causes the psoas major muscle to become infected and suppurate, forming an abscess.