Electromyography (EMG)

EMG is a test in which the electrical activity in muscle is analyzed after being amplified, displayed, and recorded. An EMG can reveal the presence of muscle disorders, or disorders in which the nerve supply to muscle is impaired. The technique for obtaining an EMG is harmless and takes 30 to 60 minutes to perform. Impulses are recorded by attaching small disk electrodes to the skin surface over the muscle or by inserting needle electrodes into the muscle. The electrical activity is evaluated during muscle contraction and at rest.