There is a kind of low back pain, mostly seen in young and strong people, with acute attacks and severe pain. Patients often lie on their sides, cannot straighten their waists, do not dare to move, do not dare to move their waists, do not dare to change positions, do not dare to get up, and cannot lie down after getting up, some patients are accompanied by pain in the buttocks and thighs. Some patients have pain in the buttocks and thighs. Most of them have severe pain during the process of bending and turning or twisting to stretching. In fact, in this case, it is generally called lumbar small joint synovial impingement, or lumbar small joint disorder, synovial joint syndrome. Etiology of pain The human vertebrae are connected by three joints, the intervertebral disc and two synovial joints. The synovial joint is composed of the inferior synovial process of the superior vertebra and the superior synovial process of the inferior vertebra. The small articular surface is covered with cartilage and has a small joint cavity surrounded by a joint capsule, the inner layer of which is the synovial membrane, which secretes synovial fluid to facilitate joint movement. The arrangement of the articular surface of the lumbar synapses is semi-frontal and semi-sagittal, and its transverse section is nearly arc-shaped, which is more flexible for extension and flexion, lateral flexion and rotation. Because the lumbosacral region has a larger range of motion, the posterior lumbosacral small joints are also more relaxed. When the lumbar region suddenly flashes and twists, bends forward and rotates, the small joint space opens up, the negative pressure inside the joint increases, and the synovial membrane can enter the joint space. If the synovial membrane is caught in the joint space during extension and flexion, it will cause synovial impaction of small joints or subluxation of small joints. The synovium can be severely damaged by compression of the joint. Synovial membrane and joint capsule have rich sensory and motor nerve fibers, thus causing severe pain and reflex muscle spasm. Treatment 1, bed rest in general, patients can find a more comfortable position to relieve pain, such as bilateral pillow under the big back, side lying pillow between the two legs, etc.. In the acute stage, patients should try to rest in bed for 1-3 days, so that the muscle spasm can be gradually relieved. 2, physical therapy local heat, infrared, spectrum and other physical therapy, can make the muscle relaxation, promote local blood circulation, improve the pain. 3.Medicine back and leg when serious, can use non-steroidal painkillers, and antispasmodic drugs, etc.. 4, small joint injection commonly known as closed.