Patients with thigh flashing pain like flashing tendons when walking are commonly caused by lumbar diseases and thigh trauma, as follows: First, lumbar diseases: lumbar disc herniation and lumbar spinal stenosis can both stimulate the nerve roots and cause radiating pain symptoms in the thigh, such as flashing-like flashing pain, the pain will come on frequently according to the degree of lesion, and the pain symptoms will persist in severe cases. Through the lumbar spine CT examination and MRI scan, the location and severity of the lumbar spine lesion will be found, and through timely treatment, the thigh pain symptoms can be completely relieved. Second, thigh trauma: in the process of sports thigh muscle strains can occur, muscle fiber tears, walking to stimulate the thigh muscle injury site will cause local pain symptoms, and accompanied by limited activity, local swelling. Physical examination will reveal the exact location of the injury, and the symptoms can be completely relieved by cold compress treatment and braking of the affected limb.