Electromyography is required when a patient is clinically suspected of having a muscle or neuropathic lesion. The commonly used EMG type is needle pole EMG, and its scope of application is as follows. 1. Needle electromyography is needed when the patient has symptoms such as numbness of limbs, pain, limb weakness, muscle atrophy, facial paralysis and so on. 2. When it is suspected that the patient may have nerve root diseases such as cervical spine, lumbar spine, etc., and nerve damage after fracture or trauma, electromyography is needed. 3. If the patient is suspected of having peripheral nerve diseases such as carpal tunnel syndrome or diabetic peripheral neuropathy, needle electromyography can be performed. 4. Electromyography is needed when there is a suspicion of neuromuscular junction diseases such as myasthenia gravis and myasthenia gravis syndrome. Surface electromyography can also be used to detect muscle contractile function and motor status. If any of the above situations occurs, the patient should follow the doctor’s advice to choose the examination method.