Deformities and Limitation of Movements of the Shoulder Girdle
The shoulder has some peculiar characteristics that need to be appreciated in order to make an accurate diagnosis of the cause of a deformity or limitation of movement of the joint. Firstly, the shoulder has such large arcs of motion in different planes that often mild degrees of limitation of motion may go undetected. This is because extreme ranges of motion are seldom required for activities of daily living. Secondly, since what appears as movement of the “shoulder” is in reality the sum total of glenohumeral and scapulothoracic motion, a fixed deformity of the glenohumeral joint may result in a compensatory posture of the scapula. In fact, this abnormal position of the scapula is what draws attention to the underlying abnormality (Fig. 26.1).