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. Author manuscript; available in PMC: 2017 Sep 6.
Published in final edited form as: J Biomech. 2016 Jun 23;49(13):2806–2816. doi: 10.1016/j.jbiomech.2016.06.018

Figure 2.

Figure 2

Degrees of freedom and rotation axes are defined according to the ISB standards (Wu et al., 2005). Shoulder degrees of freedom are for thoracohumeral motion, including thoracohumeral elevation (A), elevation plane (B), and axial rotation (A). 0° of thoracohumeral elevation is defined when the long axis of the humerus is aligned with Y axis (A), and 90° is when long axis of the humerus is aligned with Z axis (shown)., 0° elevation plane is defined when the humerus is aligned with frontal plane (B). Positive thoracohumeral elevation moves the humerus away from the thorax, positive elevation plane moves the humerus anterior (towards flexion (saggital) plane at 90°), and positive axial rotation is internal rotation. Because of the kinematic redundancy of the upper limb, it is possible to place the hand at a reach target using multiple kinematic strategies, including using an anterior strategy bringing the humerus towards the flexion plane (C) or with the humerus elevated more laterally (D).