In this paper, we present a novel kinematic framework using hybrid twists, that has the potential to improve the reliability of estimated human shoulderkinematics. This is important as the functional aspects ofthe human shoulder are evaluated using the information embedded in thoracohumeral kinematics. We successfully demonstrate in our results, that our approach is invariant of the body-fixed coordinate definition, is singularity free and has high repeatability; thus resulting in a flexible user-specific kinematic tracking not restricted to bony landmarks.