Abstract
[Purpose] The purpose of this study was to examine the influence of different elbow joint positions on shoulder joint external rotation movement using reach motion behind the auricle of the ear, measured with ultra-sound sonography. [Subjects] The subjects were twenty healthy males (average age 22.7±2.07 years old) without orthopedic or neurological problems. [Methods] We investigated the humeral external rotation angle change at 90 degrees and 0 degrees of elbow joint flexion with 90 degrees flexion of the shoulder joint. [Results] We found a significant increase in humeral external rotation in all subjects at elbow flexion of 90 degrees, compared to elbow extension of 0 degrees. [Conclusion] The results suggest that elbow joint flexion movement with glenohumeral external rotation movement is necessary for improvement of the ability to reach behind the auricle of the ear.
