Relationship between scapular initial position and scapular movement during dynamic motions

Abstract

Optimal scapular position and movement are necessary for normal function of the shoulder joint and it is essential to focus on scapula in the rehabilitation for shoulder disorders. The aim of this study was to discover the relationship between the scapular initial position and scapular movement during dynamic motions in healthy young men. Thirty-four men participated in this study. The scapular angles at initial position and in elevation and lowering during flexion and abduction were measured using an electromagnetic tracking device. The scapular movements from 30° to 120° during flexion and abduction were calculated. Spearman’s rank correlation coefficients were used to analyze the relationship between the scapular initial position and scapular movements. For upward rotation and posterior tilt of the scapula, there were significant positive correlations between the scapular initial position and scapular movement during flexion and abduction. For internal rotation, there were significant positive correlations, except 90° in lowering phase and 120° in both phases. While the humeral elevation increased, the correlation coefficients tended to decrease. Except for the internal rotation our results clarified the interactions between the scapular initial position and scapular movement during dynamic motions in healthy young men. The tendency of the decrease in correlation coefficient with elevation angle was shown.

Single or Double Plating for Acromial Type III Fractures: Biomechanical Comparison of Load to Failure and Fragment Motion

“…To ensure reproducible, physiological force transmission in the dynamic electrical testing machine (Instron E3000, Instron, Norwood, MA, USA), the specimens were clamped in an anatomically correct position with a negative mold made of polyurethane resin (RenCast FC52/53, Huntsman Advanced Materials, Basel, Switzerland). Due to the fact that the anatomical position of the scapula is dependent on arm movements, the scapula was positioned in the test machine with 15° of internal rotation, 13° of upward rotation, and 0° of anterior tilt to mimic the natural position of the scapula during 40° of arm abduction [ 16 ].…”

Improvement in scapular dyskinesis after rotator cuff repair and subacromial decompression

“…Regarding outcomes, a significantly better shoulder motion of forward flexion and higher Constant score was observed in the improved SD group, and every patient with improved SD showed successful rotator cuff healing. Full overhead flexion or shoulder joint external rotation would be difficult without posterior tilting or external rotation of the scapula [34]. In this study, posterior tilting was most prominently enhanced in the improved SD group, which may explain why the forward flexion was significantly better in the improved SD group than in the sustained SD group.…”

Feasibility of Shoulder Kinematics Assessment Using Magnetic Inertial Measurement Units in Hemiplegic Patients after Stroke: A Pilot Study

“…Causes of abnormal non-paretic upper limb kinematics have been previously discussed [11] in terms of neurological impairment due to stroke consequences on neural pathways in the contralateral hemisphere and biomechanical improper function, so the non-paretic upper limb should not be considered for comparison with the affected limb. Normally, in healthy subjects, as measured via 3D kinematic evaluation [10,12,32], during shoulder flexion, the scapula shows upward rotation and external rotation followed by internal rotation and posterior tilt, and upward, external rotation, and posterior tilt during abduction. The findings in the present study confirm the reduced posterior tilt observed by other authors [8,12,33] during arm elevation.…”