Development of a comprehensive musculoskeletal model of the shoulder and elbow

Abstract

The Delft Shoulder and Elbow Model (DSEM), a musculoskeletal model of the shoulder and elbow has been extensively developed since its introduction in 1994. Extensions cover both model structures and anatomical data focusing on the addition of an elbow part and muscle architecture parameters. The model was also extended with a new inverse-dynamics optimization cost function and combined inverse-forward-dynamics models. This study is an update on the developments of the model over the last decade including a qualitative validation of the different simulation architectures available in the DSEM. To validate the model, a dynamic forward flexion motion was performed by one subject, of which the motion data and surface EMG-signals of 12 superficial muscles were measured. Patterns of the model-predicted relative muscle forces were compared with their normalized EMG-signals. Results showed relatively good agreement between forces and EMG (mean correlation coefficient of 0.66). However, for some cases, no force was predicted while EMG activity had been measured (false-negatives). The DSEM has been used and has the potential to be used in a variety of clinical and biomechanical applications.

Fig. 1

Palpable bony landmarks on the humerus, ulna, and radius

Fig. 2

Schematic of the a IDO, b IFDO, and c IFDOC models

Fig. 3

The relative muscle forces versus normalized EMG for 12 muscles (muscle parts) during forward flexion motion. The simulations from three modeling architectures (IDO, IFDO, and IFDOC) are compared. The force and EMG are plotted against arm elevation angles (in degrees). trap ascen trapezius ascendens, trap transv trapezius transversum, trap descen trapezius descendens, infrasp infraspinatus, delt ant deltoid anterior, delt med deltoid medialis, delt post deltoid posterior, pect maj thor pectoralis major thoracic, pect maj clav pectoralis major clavicular, biceps biceps short head, triceps med triceps medialis, brachrad brachioradialis

Fig. 3

The relative muscle forces versus normalized EMG for 12 muscles (muscle parts) during forward flexion motion. The simulations from three modeling architectures (IDO, IFDO, and IFDOC) are compared. The force and EMG are plotted against arm elevation angles (in degrees). trap ascen trapezius ascendens, trap transv trapezius transversum, trap descen trapezius descendens, infrasp infraspinatus, delt ant deltoid anterior, delt med deltoid medialis, delt post deltoid posterior, pect maj thor pectoralis major thoracic, pect maj clav pectoralis major clavicular, biceps biceps short head, triceps med triceps medialis, brachrad brachioradialis

Fig. 4

The predicted resultant reaction force in the glenohumeral joint by the IDO, IFDO, and IFDOC models versus arm elevation angle during forward flexion motion. GHJRF glenohumeral joint reaction force