Ergonomic analysis of postural and muscular loads to diagnostic sonographers

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 >30o shoulder abduction, 63% with >30o shoulder outward rotation, and 37% with the neck bent forward, laterally or twisted >20o. 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.Relevance to industryDiagnostic sonographers experience long durations in static shoulder abduction and outward rotation, with high peak and sustained grip forces. These risk factors are consistent with the high prevalence of neck and upper limb musculoskeletal disorders and symptoms reported by many sonographers.