In veterinary practice electromyography is a useful diagnostic technique for differentiating neuropathies, junctionopathies, and myopathies. The electromyogram gives information on the state of activity of motor neurons at rest, in reflex contraction, and in voluntary contraction. As a research tool, the electromyogram can be used to understand the complexity of the neuromuscular system. It has applications in horses for assessing muscle activation patterns and for providing a more complete understanding of the pathology of the muscles and nerves.