Electromyography (EMG) is a test to record electrical activity of nerves and muscle so as to determine the function of peripheral nerve, neuron, neuromuscular junction and muscles. It is used to diagnose nerve and muscle dysfunction and spinal cord disease.

During the procedure of EMG, very fine wire electrodes are inserted into a muscle to evaluate the changes in electrical voltage that occur during movement and when the muscle is at rest. The electrodes are attached through a series of wires to a recording instrument. Testing usually takes place at a testing facility and lasts about an hour but may take longer, depending on the number of muscles and nerves to be tested.