Which structure in the shoulder joint helps deepen the socket?

The labrum is a key structure in the shoulder joint that plays a vital role in deepening the glenoid cavity, which is the socket part of the ball-and-socket joint. It is a fibrocartilaginous structure that encircles the glenoid, increasing the surface area for the humeral head to articulate. This addition helps stabilize the joint by providing a deeper fit and improving overall joint congruency, which is crucial for the wide range of motions the shoulder allows.

The labrum also serves to protect the underlying bone and enhances the attachment for the ligaments and tendons connected to the shoulder, further contributing to joint stability during movement. In contrast, tendons primarily serve to connect muscles to bones and facilitate movement; bursae are fluid-filled sacs that reduce friction between tissues, while ligaments connect bones to other bones and provide stability but do not specifically deepen the socket. This anatomical understanding is essential for recognizing how joint structures contribute to function and stability in human movement.