Innervation zone locations in 43 superficial muscles: toward a standardization of electrode positioning.

ABSTRACT

INTRODUCTION: We describe the innervation zone (IZ) location in 43 muscles to provide information for appropriate positioning of bipolar electrodes for clinical and research applications. METHODS: The IZ was studied in 40 subjects (20 men and 20 women) using multichannel surface electromyography (sEMG). Signal quality was checked visually to identify motor unit action potentials and estimate muscle fiber conduction velocity. RESULTS: Results in 33 muscles were classified as excellent or good, because it was possible to identify an area which is favorable for appropriate positioning of an electrode pair without the need to previously determine the IZ location. CONCLUSIONS: Knowledge of IZ location will increase standardization and repeatability of sEMG measures.