Understanding the Basics of Electromyography (EMG)

An EMG is a test of normal versus abnormal electrical activity in the muscles and nerves. If you have pain, numbness, burning, weakness, tingling or other symptoms of nerve irritation, they may be coming from an injury to either your peripheral nerves or nerve root. An EMG helps determine which it is, and can be a very useful tool in determining your treatment options.

The areas where a nerve comes out of the spinal cord are called nerve roots. From there they divide into nerve branches that become peripheral nerves. Many patients have radiating pain caused by pressure on nerve roots. This can occur when there are structural lesions of the spine such as herniated disc, bone spurs, and/or degenerative arthritic narrowing. In simple terms, if a person has a pinched nerve in the spine or extremity, an EMG can determine where it is pinched, how severely it is pinched, and if there is evidence of permanent or temporary damage. It can also distinguish between injury to different types of nerves and differentiate nerve trauma from nerve disease.

The value of the testing is in trying to accurately determine the location and severity of the injury. From there, the physician can best determine whether the patient needs a procedure and what kind of procedure.