Electromyography is generally required in the following cases: first, for cases where there may be nerve damage. For example, the patient has some limb fracture, dislocation, or is accompanied by serious local soft tissue injury. At this time, in some nerve pathways, may cause damage to the nerve, in the process of examination of patients, it is necessary to do electromyography to clarify whether there is damage to the nerve conduction pathway. Second, for some muscle weakness, some patients may have some unexplained muscle weakness, at this time, electromyography is needed to check whether there are nerve-related lesions that cause muscle weakness. Third, for some possible peripheral nerve entrapment, some patients may have some local muscle weakness and abnormal sensory function, at this time, if the doctor suspects that there is some peripheral nerve entrapment, electromyography will also be arranged. Fourth, for some sensory dysfunction, for example, some patients may have local pain and numbness in a certain area, for this series of sensory abnormalities, also need to arrange electromyography examination. Fifth, for some peripheral nerve injuries or lesions, EMG is also needed after a period of treatment to clarify the recovery of the nerve.