You feel pain, heat, cold and other sensations, walk, run, laugh, dance and even remember to pick up the dry cleaning because of the nerves in your body.

Nerves are electrical conductors, sending messages to and from your brain. Sensory nerves send messages about your environment to the brain, which "listens" to the messages. Your brain then makes a decision and sends the appropriate action to your muscles using motor nerves. Sensory nerves tell your brain if your hand is too close to a hot iron; motor nerves tell your muscles to pull your hand away from the iron.

Injury or disease may disrupt the messages traveling to and from your brain, causing pain, weakness or numbness in the back, neck, arms, hands or legs. Electrodiagnostic testing is used to help pinpoint the problem. Two tests commonly used are electromyography (EMG) and nerve conduction studies (NCS).

During an EMG, sterilized small, thin needles are used to evaluate the electrical activity in your muscles. An EMG allows the physician conducting the study to see and even listen to muscle activity, which lets the physician determine if the muscle is functioning normally.

NCS are used to determine if nerves are working correctly and are often done with an EMG. During NCS, electrodes are taped to the skin over the muscle being tested.  A small electrical current is sent to your nerves through the electrodes. The faster the electrical current travels through the nerves, the healthier the nerves. Weakened or damaged nerves will produce slow, weak signals.

According to the American Academy of Orthopaedic Surgeons, common conditions often requiring electrodiagnositc testing to diagnose include:

• Carpal Tunnel Syndrome: The median nerve travels from the forearm to the hand through the carpal tunnel in the wrist. Carpal tunnel syndrome occurs when the median nerve is "squeezed" at the wrist, resulting in numbness and tingling in the hand.
• Ulnar Nerve Entrapment: Also called cubital tunnel syndrome. When you hit your elbow or "funny bone" and feel a tingling sensation, it is because you disturbed the unlar nerve. This long nerve extends down the arm, behind the elbow through the cubital tunnel and into the hand. It is responsible for feeling and muscle activity in the little and ring finger, and many muscles in the hand.  Injury to the elbow may cause the ulnar nerve to swell and become "trapped" in the cubital tunnel.
• Cervical Radiculopathy: Radiculopathy refers to pain "radiating" from the cervical area, or neck, typically caused by pressure on the nerve "roots" as they leave the spinal column near the neck.
• Thoracic Outlet Syndrome: The space between your collarbone and first rib is called the thoracic outlet. This tight space consists of many blood vessels, muscles and nerves. Thoracic outlet syndrome occurs when the shoulder muscles are not strong enough to hold the collarbone in place, and it "slips" down putting pressure on the blood vessels, muscles and nerves in the thoracic outlet.

Orthopedics is the area of medicine specializing in the diagnosis and treatment of bone, joint, tissue and nerve disorders. Electromyography and nerve conduction studies help orthopedic specialists properly diagnose and determine the best treatment for muscle and nerve disorders.

If you are experiencing pain, weakness or numbness in the back, neck, arms, hands or legs, it is important to identify and treat the cause. Talk with your primary care physician about a referral to Valley Orthopedic Associates for electrodiagnostic testing, or call VOA at 425-656-5060.

Additional Resources:
American Academy of Orthopaedic Surgeons
North American Spine Society