An Electromyograph (EMG) is defined as a test which measures muscle response to nerve stimulation. It is used to evaluate muscle weakness and to determine if the weakness is related to the muscles themselves or a problem with the nerves that supply the muscles.
Abnormal results may be seen in Myasthenia gravis, Polymyositis, Carpal tunnel syndrome , Amyotrophic lateral sclerosis , Alcoholic neuropathy, Cervical spondylosis, Dermatomyositis, Familial periodic paralysis, Guillain-Barre syndrome, Lambert-Eaton syndrome, Friedreich's ataxia , mononeuritis multiplex, peripheral neuropathy, sciatic nerve disease and a variety of peripheral nerve disorders.