There is a type of lumbar injury that occurs immediately after the injury with unusually severe back pain. Patients are often bent sideways, the waist can not straighten, afraid to move, but afraid that others touch, often misdiagnosed as acute lumbar sprain. In fact, the exact diagnosis should be lumbar joint synovial imbrication, or called lumbar posterior joint disorder, commonly known as small joint disorder. The human lumbar spine, its posterior joint consists of the lower synovial process of the upper vertebrae and the upper synovial process of the lower vertebrae. The small joint surface is covered with cartilage, has a small joint cavity, surrounded by the joint capsule, and its inner layer is the synovial membrane, which can secrete synovial fluid to facilitate joint movement. The arrangement of the articular surface of the lumbar synapses is semi-frontal and semi-sagittal, and its cross-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 gap opens up, the negative pressure inside the joint increases, and the synovial membrane can enter the joint gap. If the synovial membrane is caught in the joint space during extension and flexion, it will cause synovial imbrication of small joints or subluxation of small joints. The synovium can be severely damaged by compression of the joint. The synovium and joint capsule are rich in sensory and motor nerve fibers, which cause severe pain and reflex muscle spasm. If the impingement is not released in time, chronic severe back pain and arthritis can develop. Treatment Manual therapy is an effective treatment for this disease. If the diagnosis is clear, immediate results can be obtained after manipulation. The commonly used method is: “diagonal reverse back”, that is, the patient is back to back, the affected area against the operator’s buttocks, the operator bends forward, so that the patient’s feet are off the ground, and swing from side to side, and then the buttocks suddenly a top, embedded strangulation can be released. This method is suitable for doctors who are taller and patients who are thinner, on the contrary, doctors who cannot afford to carry patients cannot achieve the effect. In addition, the lateral recumbent waist pulling method or the seated waist lifting and pushing method can also release the embedded and strangulated lock. The pain physician also has a great skill in treating this disease, that is, small joint block. The analgesic and anti-inflammatory drugs are injected into the painful small joints, and the patient’s back muscles relax due to the elimination of pain.