Surface EMG evaluation of sonographer scanning postures

Abstract

This article presents a technique for quantitative evaluation of musculoskeletal impact using postural tests to assess two specific muscle groups: the left upper trapezius and the right suprascapular fossa. The muscular activity of these regions of the neck and shoulder was quantitatively evaluated using surface electromyography in 22 sonographer subjects. This study shows statistically significant reductions in muscle activity by modifying scanning technique and workstation arrangement. Left upper trapezius muscle activity decreased 65% from a 50-degree forward shoulder flexion (reach) to neutral (0-degree reach) position. Right suprascapular fossa activity decreased 46% between a 75-degree abduction and 30-degree abduction, as well as 78% when support under the forearm at the same 30-degree abduction was provided, resulting in a total reduction from the first position to the third position of 88%. These results illustrate the benefit of optimized scanning technique, workstation utilization, and use of adjustable workstation equipment.