Ergonomic analysis of postural and muscular loads to diagnostic sonographers

摘要

Musculoskeletal disorders are prevalent in diagnostic sonographers. This study quantifies the postural and muscular loads during ultrasound scanning. Video-based stop-motion postural analysis at 4 samples/minute for 24 full scans (527.5 minutes) by 11 sonographers showed sonographers spend 68% of scanning time with >30° shoulder abduction, 63% with >30° shoulder outward rotation, and 37% with the neck bent forward, laterally or twisted >20°. The shoulder was observed to be unsupported, or static, for 73% of scanning time and this was significantly higher for carotid scans compared with abdominal, obstetrical or leg scans (p<0.05). Electromyography (EMG) was collected for seven scans performed by three sonographers on three shoulder muscles: Supraspinatus, infraspinatus, and trapezius; as well as for flexor carpi ulnaris. Static (0.10) amplitude probability distribution functions (APDFs) for all three shoulder muscles exceeded 3% MVC corresponding to a "medium" risk rating for shoulder-neck disorders. Mean forearm flexor EMG was 3.96 kg (SD 2.94), with occasional peak forces as high as 27.6 kg.