“…2,3,4 While the natural history of the changes in bone and articular alignment has been extensively studied, the pathogenesis of muscular changes preceding them remains unclear and is currently receiving more attention. [5][6][7]8,9,10 The mechanism leading to subscapularis muscle growth impairment with subsequent volume loss and contracture has been explained by two differing hypotheses: denervation 8,11,9,12 and muscle imbalance. 5,6,7,13,14,10 The imbalance theory infers that the subscapularis changes are secondary to the lack of passive stretching in the absence of active shoulder external rotation, which leads to progressive shortening and stiffness of subscapularis muscle due to an abnormal muscle growth or muscle hypoplasia.…”