Description | Indications | Mechanism | Limitations | Risks

Electromyograms - Spinal diagnostic test

Description:

An electromyogram or EMG is a test to determine how well the nerve roots leaving the spine are functioning. The EMG measures the degree to which an electrical current is transported by the nerve to the muscles, and also measures the electrical activity in muscles.

Indications:

EMG and nerve conduction tests can determine if there is a pinched nerve, the severity of the damage, and often the location of the problem. The EMG, therefore, provides information concerning the condition of nerves that stimulate the muscles.

Mechanism:

During the EMG test, small acupuncture-like needles are placed into the muscles of the arm or leg, and electrical signals are recorded. The nerve is then stimulated, and the time it takes the electrical signal to make the muscle twitch is measured and recorded.

Limitations:

The EMG provides information concerning the transmission of electrical impulses down the nerve to the muscles. If there is an abnormality, however, the EMG does not diagnose the problem or otherwise provide information about the nature of the problem. Sometimes, the EMG may also appear normal, even when nerve damage is present.

Risks:

Infection from the insertion of the needle occurs very rarely.