The human cervical myotomes: an anatomical correlation between electromyography and CT/myelography.

To correlate the accuracy of electromyography in diagnosing the correct root involved in cervical radiculopathy, 20 patients with cervical radiculopathy, diagnosed by electromyography using strict inclusion and exclusion criteria, were studied. Metrizamide myelography/computerized tomography were evaluated in all 20 patients independently, and the involved root was defined. The root involved, using the EMG examination and the myotome chart of the Medical Research Council, was C5 in 3 patients, C6 in 6, C7 in 9 patients, and C8 in 2 patients. The overall correlation with myelography/CT was 65% (33.3, 66.6, 77.7, and 50% for C5, C6, C7, and C8, respectively). EMG done properly has a good correlation of myelography/CT. This correlation is higher (73.3%) for the commonly occurring cervical radiculopathies (C6 and C7).