The causes of muscle relaxation include physiological causes and pathological causes, such as neuromuscular lesions, arthropathy, cerebral infarction, cerebral hemorrhage, and malnutrition. 1. Physiological reasons: such as long time inactivity, or the old people in the age of muscle atrophy, the muscle becomes flaccid. 2. Neuromuscular lesions: for example, radiculitis, poliomyelitis, muscular dystrophy, metabolic myopathy, which can lead to muscle atrophy and relaxation. 3. Joint lesions: for example, osteoarthritis, rheumatoid arthritis due to joint pain, joint movement caused by the lack of wasteful muscle atrophy. 4. Cerebral infarction, cerebral hemorrhage: one or both limbs have unfavorable movement and muscle atrophy due to hemiplegia. 5. Malnutrition: muscle atrophy due to protein deficiency caused by consumptive diseases such as tuberculosis, tumor, gastrointestinal diseases. If there is muscle atrophy and flaccidity, it is necessary to go to the hospital for further examination to clarify the cause of the disease for further treatment.