Which structure helps maintain the round shape of the glenohumeral joint?

The glenoid labrum is a fibrocartilaginous structure that deepens the glenoid cavity of the scapula, where the head of the humerus articulates to form the glenohumeral joint. By increasing the depth of the glenoid fossa, the labrum plays a critical role in stabilizing the humeral head within the joint, allowing for a more secure fit and contributing to the overall round shape of the joint. This stability is essential for the wide range of motion that the shoulder joint provides.

Other structures, like the rotator cuff, support the joint by providing dynamic stability through muscular attachment and activation, but they do not directly contribute to maintaining the round shape of the joint. The coracoacromial arch and acromion process provide additional support and protection to the joint but are also not primarily responsible for preserving the round configuration of the glenohumeral articulation. Thus, the glenoid labrum is uniquely positioned to maintain the integrity of the joint's shape and stability.