Surface EMG Evaluation of Sonographer Scanning Postures

Objectives This paper presents a technique for general quantitative evaluation of musculoskeletal impact through the evaluation of postural tests to assess two specific muscle groups. The two muscle groups chosen were the left upper trapezius, utilized while operating an ultrasound system’s control panel, and the right suprascapular fossa, utilized while scanning. Surface electromyography (SEMG) was used to quantitatively measure muscular activity of these regions of the neck and shoulder. Methods Twenty-two sonographers subjects were evaluated using surface electromyography (SEMG) while performing standardized tasks typical of Diagnostic Medical Sonographers. SEMG was used to compare muscular activity in specific muscle(s) associated with postures employed to perform these tasks. Results This study shows large and statistically significant reductions in muscle activity by modifying scanning technique and workstation arrangement. The left upper trapezius muscle activity decreased 65% by changing from a 50 ̊ forward shoulder flexion (reach) to a neutral (0° reach) position. The right suprascapular fossa activity showed a reduction of 46% between a postural stance of 75° abduction and 30° abduction. There was an even more dramatic reduction of 78% by providing support under the forearm at the same 30° abduction. Consequently, the total reduction from the first position to the third position was demonstrated to be an 88% decrease in muscular activity.