The shoulder complex is composed of articulations between the humerus, glenoid, scapula, acromion, clavicle, and the surrounding soft tissue structures that connect them. The shoulder complex allows for a large degree of motion in multiple planes at the expense of stability. As a result, this compound set of articulations can present a diagnostic and treatment challenge.
The rotator interval, according to Neer,1 is the capsular tissue in the interval between the subscapularis and the supraspinatus tendons. The structures within the rotator interval contribute to the stability of the shoulder by limiting inferior translation and external rotation with the arm adducted, as well as posterior translation when the arm is forward flexed, adducted, and internally rotated.
The specific joints of the shoulder complex include the following:
If optimal shoulder function is to occur, motion also has to be available at the cervicothoracic junction and at the connections between the first three ribs and the sternum and spine.