Tests and diagnosis

By Mayo Clinic Staff

To help diagnose the extent and severity of a brachial plexus injury, you may have one or more of the following tests:

  • Electromyography. This test checks the health of the nerves that help move your muscles. After small needle electrodes are inserted through your skin into a muscle, you're asked to contract that muscle. The amount of electrical activity generated provides information about how well the muscle responds when its nerves are stimulated. You may feel a little pain when the electrodes are inserted, but most people can complete the test without much discomfort.
  • Nerve conduction studies. These measure how quickly impulses are conducted through a nerve. Your nerve is stimulated through a patch-like electrode attached to your skin. This stimulation can feel like an electric shock of varying intensity. Although this test can be uncomfortable, you won't have any lingering pain afterward.
  • Magnetic resonance imaging (MRI). An MRI uses radio waves and a powerful magnetic field to visualize structures in your body. It often can show the extent of the damage caused by a brachial plexus injury. This test is typically used to determine if a nerve has been severed completely from your spinal cord. New methods of high resolution MRI, known as magnetic resonance neurography (MRN), may be used.
  • Computerized tomography (CT) myelography. A myelogram is a type of imaging that uses a contrast material, injected during a spinal tap, to produce a detailed picture of your spinal cord and nerve roots. In CT myelography, the images are taken with a CT scanner, a device that uses X-rays to create cross sections of body tissues. This test is sometimes performed when MRIs don't provide adequate information. Your doctor may tell you to drink more water the day before the test, and you may need to stop taking certain medications for a few days before a myelogram. Side effects of the test can include headache and nausea.
Feb. 24, 2011