Medial paraspinal muscle electromyography: techniques of examination

We describe two techniques, developed through cadaveric dissections, for the electromyographic examination of the lumbar interspinal muscles and medial lumbar multifidi. Previous anatomic studies have indicated that these medial paraspinal muscles share unisegmental innervation by a single nerve root. Electromyography of these muscles may therefore improve the localization of lumbosacral radiculopathy. The ability of the two techniques to achieve appropriate needle placement was confirmed using percutaneous injection of colored latex into cadavers. The safety and feasibility of the techniques were confirmed in healthy volunteers. Further studies are underway in subjects with lumbosacral radiculopathy to determine the clinical utility of these techniques.