Electromyography (EMG) is a diagnostic technique used to evaluate the electrical activity of muscles and nerves. It is often used to diagnose neuromuscular disorders, such as muscular dystrophy, myasthenia gravis, and peripheral neuropathy.

During an EMG test, a small, thin needle electrode is inserted through the skin into the muscle being studied. The electrode detects the electrical activity of the muscle while it is at rest and during contraction. The electrical signals are amplified and displayed on a monitor, allowing the technician or doctor to analyze the muscle activity.

In addition to detecting muscle and nerve disorders, EMG can also be used to determine the severity of a disorder and monitor treatment progress. The test is usually performed in a hospital or clinic setting and takes approximately 30 to 60 minutes. It is generally considered a safe and painless procedure, although some patients may experience mild discomfort while inserting the needle electrode.