The lack of congruence between the involved articular surfaces causes the inherent instability of the glenohumeral joint. This joint is therefore the most commonly dislocated joint in the human body. Anterior instability accounts for over 90% of the shoulder dislocations. The reason of this almost unidirectional dislocation remains unknown. Few studies have quantitatively discussed the joint stability utilizing musculoskeletal models. Other studies mainly utilized either purely clinical or cadaveric approaches to address the joint stability. The aim of this study is to identify the key factors contributing to anterior instability through a quantitative analysis of the shoulder's dynamic stabilizers.