Stability of the glenohumeral articulation is dependent on the integrity of the rotator cuff, labrum, glenohumeral ligaments, capsular elements, and bony glenoid. The importance of the soft-tissue elements in maintaining stability has been well documented in the surgical literature but has only recently been introduced into the radiologic literature. The purpose of this essay is to illustrate the normal labrum, capsular complex, and glenohumeral ligaments, including common congenital variations as depicted by CT arthrography and MR imaging, and to describe the pathologic findings leading to shoulder instability.