Normally, a muscle at rest has no electrical activity. The muscle contraction itself also produces electrical activity. (These signals originate in your brain, travel down your spinal cord, through your motor nerves and to your muscles.) This electrical stimulation causes electrical activity in your muscles, which causes them to contract (tighten). Your motor nerves (motor neurons) send electrical signals to your muscles to tell them what to do. To understand how an EMG test works, it helps to understand how your muscles work. Providers use other tests in conjunction with electromyography to diagnose these conditions, such as imaging tests, blood tests and muscle biopsies. Conditions that affect the connection between your nerves and muscles, such as myasthenia gravis.Conditions that affect the motor neurons in your brain or spinal cord, such as amyotrophic lateral sclerosis (ALS) or post-polio syndrome.Muscle disorders ( myopathies ), such as muscular dystrophy, polymyositis and dermatomyositis.Issues that affect the nerve roots that exit your spinal column, such as pinched nerves, cervical (neck) radiculopathy or sciatica.Issues that affect your peripheral nerves, such as peripheral neuropathy and nerve compression syndromes like carpal tunnel syndrome.Providers may also use EMG tests to rule out conditions.Ĭategories of conditions an EMG can help diagnose include: It can help determine the presence, location and extent of these injuries and diseases. What can an EMG diagnose?Īn EMG can help diagnose several injuries or diseases that affect your motor nerves and muscles.

You may have an EMG in an outpatient setting or as part of your stay in a hospital, depending on your situation. Your healthcare provider may recommend an EMG if you have symptoms such as muscle weakness or numbness and tingling. An EMG measures the response of muscles to electrical activity and how much electrical activity a muscle contraction produces. An NCS measures the flow of electrical current through a nerve before it reaches a muscle. Neurologists often perform an EMG test alongside a nerve conduction study (NCS). An EMG can detect issues with your motor nerves, muscles or the communication between the two. To produce movement, your motor (movement) nerves send electrical signals to your muscles. It’s one form of electrodiagnostic testing.Įvery body movement you make, from lifting your leg to nodding your head, involves complex communication between your central nervous system (your brain and spinal cord), nerves and muscles. What is an EMG (electromyography)?Įlectromyography (EMG) is a diagnostic test that evaluates the health and function of your skeletal muscles and the nerves that control them. Electromyography (EMG) is a diagnostic test that evaluates the health and function of your skeletal muscles and the nerves that control them.

Nerve conduction test on neck