How is it performed?
In an EMG, a physician or technician inserts a very fine needle, which serves as an electrode, through the skin into the muscle. With the electrode in place, the patient is asked to slowly contract the muscle—for example, by bending the arm—with gradually increasing force, while the electrical activity is being recorded. The activity can be displayed visually on an oscilloscope or screen, or played audibly through a speaker. The results can provide information about the ability of the muscle to respond to nerve stimulation.