Background: Shoulder function is achieved by the coordinated movements of the scapula, humerus, and thoracic spine, and shoulder disorders can be associated with altered scapular kinematics. The trunk plays an important role as the kinematic chain during arm elevation.
Objects: The purpose of this study was to determine the effects of thoracic hyperkyphosis on scapular orientation and trunk motion.
Methods: Thirty-one subjects (15 in the ideal thorax group and 16 in the thoracic hyperkyphosis group) performed right-arm abduction and adduction movements in an unconstrained plane. The scapular orientation and trunk motion were recorded using a motion analysis system.
Results: Those subjects with thoracic hyperkyphosis displayed greater scapular posterior tilting at a 120˚ shoulder elevation, greater scapular internal rotation throughout the arm raising phase, and greater trunk axial rotation at the upper ranges of the shoulder elevation, compared to those subjects with an ideal thorax (p<.05).
Conclusion: Thoracic hyperkyphosis can cause scapular instability, greater trunk rotation and greater scapular posterior tilting, and may contribute to preventing the achievement of a full range of humeral abductions in an unconstrained plane.

Abstract
Introduction
Methods
    Thoracic angle measurement
    Subjects
    Data acquisition
    Data analysis
    Experimental procedure
    6. Statistical analysis
Results
    Scapular orientation
    Trunk motion
Discussion
    Scapular orientation
    Limitations
Conclusion
References

• Jae-man Park(Dept. of Physical Therapy, College of Graduate School, Daejeon University)
• Jong-duk Choi(Dept. of Physical Therapy, College of Health & Medical Science, Daejeon University) Corresponding author
• Song-i Han(Dept, of Physical Therapy, Daejeon Barun mind hospital)