Motions of the Bones and Activation of the Muscles of the Shoulder Girdle During Basic and Common Arm Movement

A comprehensive understanding of healthy shoulder motion is a valuable contribution to the academic literature and provides a basis of comparison for various shoulder pathologies and treatments. However, the medical community is primarily interested in how pathology affects shoulder function and the underlying musculoskeletal reasons for impaired function associated with specific pathologies. Rotator cuff tears (RCT) provide an excellent model to study shoulder biomechanics because RCTs can cause significant functional impairment and can be quantified in size and location using standard clinical imaging techniques. Upon completion of this study a comprehensive database of three-dimensional joint angles and EMG patterns of the structures of the shoulder joint complex of dominant and non-dominant during common activities of daily living will be available for healthy subjects and those of subjects whose dominant limbs are impaired by rotator cuff tears. These data will show normal muscle activations and movement patterns required to complete activities of daily living and compare them to the movement, and muscle activation patterns of persons who exhibit muscular and movement dysfunction due to rotator cuff tears.