Many conditions can be diagnosed with a simple physical exam, but in a closed system like the human body, further testing is often required to determine the cause of pain or the extent of an injury.

Orthopaedists commonly use x-rays, computed tomography (CT) scans, magnetic resonance imaging (MRI), and electrodiagnostics to get a more complete picture of your condition, prior to outlining a treatment plan. Many of these tests can be conducted on site at our MedPlex location.

Electrodiagnostic Testing

About Electrodiagnostic Testing

Did you know that your body is an electrical generator? Nerves and muscles create electrical signals that deliver messages to and from your brain. Injuries or diseases can slow or or even stop the movement of these electrical signals.

If you experience pain, weakness or numbness in your back, neck or hands, your physician may want to measure the electrical activity in your nerves and muscles to help him diagnose the cause. This process is called electrodiagnostic testing.

Two tests are commonly used:

  • Electromyography (EMG)
  • Nerve conduction studies (NCS)

These tests are usually administered by a neurologist (a doctor who specializes in the study of the nerves) or a physiatrist (a specialist in rehabilitation medicine). The tests can often be done in less than an hour.

Your orthopaedist may recommend electrodiagnostic testing for various conditions that can result from pressure on a nerve, particularly in the arm, elbow or wrist. These conditions are called “compressive neuropathies” and include:

  • carpal tunnel syndrome (pressure on the median nerve as it passes between the wrist bones and under the transverse ligament)
  • thoracic outlet syndrome (pressure on the brachial plexus, a cluster of nerves that passes under the collarbone at the shoulder)
  • ulnar nerve entrapment (pressure on the ulnar nerve as it passes behind the elbow)
  • cervical radiculopathy (pressure on the nerve roots as they exit the spinal column at the neck)

Electrodiagnostic testing also can be used to determine the extent of injury to a nerve after an accident and to study the effects of diseases such as diabetes.


An EMG records and analyzes the electrical activity in your muscles. It is used to learn more about the functioning of nerves in the arms and legs. When a normal muscle is at rest, it is electrically silent.

During an EMG, small, thin needles are placed in the muscle to record the electrical activity. The doctor will ask you to relax the muscle and to tense it slightly. The doctor will listen and watch a computer screen that broadcasts the electrical signals. You will also be able to hear the signal sounds as you move the muscle. There are no long-term side effects. Usually, you can get the results immediately after the test.

Nerve Conduction Study

An NCS is often done along with the EMG to determine if a nerve is functioning normally. The doctor conducting the test will adhere wires (electrodes) to the skin in various places along the nerve pathway. Then the doctor stimulates the nerve with an electric current. As the current travels down the nerve pathway, the electrodes placed along the way capture the signal and time how fast the signal is traveling.

In healthy nerves, electrical signals can travel at up to 120 miles per hour. If the nerve is damaged, however, the signal will be slower and weaker. By stimulating the nerve at various places, the doctor can determine the specific site of the injury.

Magnetic Resonance Imaging (MRI)

An MRI device is basically a sophisticated scanner. It uses a powerful magnet, radio waves and a computer to create detailed images of the internal structures of the body. Because a magnetic resonance image displays excellent contrast between the different types of soft tissue, it is invaluable in evaluating injury and illness, especially in muscles and joints.

Southlake Orthopaedics has its own MRI on site, which makes scheduling your test fast and easy. We offer flexible scheduling to help accommodate your busy work and family schedule.

Our MRI facility is accredited through the American College of Radiology and staffed with Board Certified Radiologists and ARRT Certified Technologists. We are equipped with the Hitachi Echelon™ 1.5 Tesla machine, which is a “short bore” magnet model. This means it is about half the length of a standard MRI, and patients are positioned feet first for the test. Many who have anxiety about tight spaces find this type of MRI more comfortable.

Additionally, the Echelon™ can handle patients who are heavy (weighing up to 500 pounds), as well as being designed with stabilizers to help compensate for motion if a patient is unable to remain completely still.

Additional testing available on-site:

  • X-ray
  • Arthrography of the Hip and Shoulder (A series of images, commonly X-rays, taken after the injection of a contrast dye that helps provide shaper, more perceptible information to the diagnosing physician; sometimes performed in conjunction with a CT or MRI scan.)
  • Flexibility Tests
  • Functional Baseline Evaluation
  • Arthrocentesis/Joint Aspiration (A procedure using a syringe to collect the synovial or lubricating fluid from a joint capsule.)
  • Laboratory Studies
  • Muscle Tests