Lumbar spine rotation crunch may be physiological phenomenon, lumbar spine small joint disorder, lumbar spine degenerative changes and other reasons. 1. Physiological phenomenon: usually the human body lumbar spine activity process, due to the joints or ligaments across the bone protrusion of the sudden friction, lumbar vertebrae rotation will make a crunch, which is a normal physiological phenomenon. 2. Disorders of the small joints of the lumbar vertebrae: Disorders of the small joints of the lumbar vertebrae may also lead to lumbar vertebrae rotation crunching, usually only the sound, will not be accompanied by other symptoms, which is mainly caused by long-term sedentary, prolonged standing and other factors. 3. Degenerative changes of lumbar vertebrae: Generally, degenerative changes of lumbar vertebrae will cause herniated intervertebral discs and degenerative changes of articular cartilage, which will lead to localized mutual wear and tear, and the joint surfaces are not smooth. Therefore, sudden activity of the lumbar spine may lead to lumbar spine rotation rattling, and accompanied by lumbar activity limitation, pain and other symptoms. There are many other causes of lumbar spine rotation rattling, it is recommended that patients seek timely medical treatment to clarify the cause of the disease and standardize the treatment.