Electromyography of the Paraspinal Muscles: Technical Instructions, Indications and Diagnostic Utility

Electromyographic examination of the paraspinal muscles is not an inherent part of the electrophysiological investigation. In some situations, however, electromyographic examination of the paraspinal muscles provides important information supplementary to the findings in the muscles of the extremities. Fibrillations and positive sharp waves in the paraspinal muscles are easily assessed. Because of the different sizes of the motor unit potentials of the cervical, thoracal and lumbar paraspinal muscles and the limitations of single motor unit potential analysis in daily routine, the differentiation between a neurogenic and a myopathic process remains difficult. Localisation of the damaged nerve root is not possible, because the paraspinal muscles are innervated polysegmentally. It must be taken into account that lesions of the brachial und lumbar plexus (neuralgic amyptrophy, diabetic amyotrophy) may include the nerve roots. Finally, electromyography of the paraspinal muscles constitutes a useful tool in the diagnosis of anterior horn diseases.