Electromyography (EMG) is a technique used to evaluate the function of nerves and muscles by recording the electrical activity produced by the skeletal muscles. It is an important test used to diagnose neuromuscular disorders. It is often used to evaluate disorders of the peripheral nervous system (nervous system outside the brain and spinal cord).
Electromyography involves the insertion of a pin electrode (tiny needle) through the skin into the muscle tissue. Electrical activity of the muscle is then recorded on a computer. The results allow the neurologist to diagnose any abnormal muscle or nerve activity. This test helps to differentiate between a nerve root disorder and muscle disease.