The disabled throwing shoulder: spectrum of pathology part III: the SICK scapula, scapular dyskinesis, the kinetic chain, and rehabilitation

Internal Rotation Deficits Affect Scapular Positioning in Baseball Players

“…External rotation gain and GIRD occur in healthy overhead-throwing athletes [2,3,8,29], and some authors theorize the deficit places the shoulder at a higher likelihood of having an injury as a result of an altered distribution of stress [6,22,38,39]. The direct cause of these alterations has yet to be determined.…”

“…Some believe increases in external rotation occur over several years and are associated with the repetitive stretching of the anterior capsule [9,10,22,27,28]. Based on surgical observations, others have suggested the internal rotation deficits are a result of an acquired hypertrophied posterior capsule [5,6,31,39]. It is thought that a thicker posterior capsule would have increased structural stiffness, thereby limiting internal rotation [5,6,31,39].…”

“…Based on surgical observations, others have suggested the internal rotation deficits are a result of an acquired hypertrophied posterior capsule [5,6,31,39]. It is thought that a thicker posterior capsule would have increased structural stiffness, thereby limiting internal rotation [5,6,31,39]. Finally, others believe both are caused by an increase of humeral retroversion [8,32,33,35].…”

“…Regardless of the direct cause of the internal and external rotation alterations, some studies suggest an association with injury to the rotator cuff and labrum [6,16,21,31]. Abnormalities such as partial undersurface rotator cuff tears, internal impingement, and posterior SLAP lesions are common in these athletes.…”

“…Abnormalities such as partial undersurface rotator cuff tears, internal impingement, and posterior SLAP lesions are common in these athletes. Some authors have described static (positional) and kinematic (motion pattern) abnormalities (scapular dyskinesis) of the scapula in relation to the thoracic cage [6,19,23,30,40]. These alterations, commonly identified in baseball throwers, include increased protraction, anterior tilting, and decreased upward rotation [6,23,30].…”