What is the function of the glenoid labrum?

The glenoid labrum is a fibrocartilaginous structure that surrounds the glenoid cavity of the scapula, which is the socket part of the shoulder joint. Its primary function is to deepen the glenoid fossa, providing a more stable and secure fit for the head of the humerus (the upper arm bone) within the shallow socket of the scapula. This deepening improves the congruence of the joint, allowing for a greater range of motion while contributing to the stability of the shoulder joint. By enhancing the socket, the glenoid labrum plays a critical role in facilitating the complex movements of the shoulder while also helping to absorb some of the shock forces that occur during activities involving the upper limb.

While other options may touch on aspects related to shoulder function or anatomy, they do not accurately reflect the specific and primary role of the glenoid labrum in stabilizing the shoulder by deepening the glenoid fossa.