The rim of soft tissue located on the periphery of the glenoid fossa that adds stability to the glenohumeral joint is called the glenoid labrum.
Step-by-step explanation:
Glenoid cavity is the place where the humerus joins with the scapula. Glenoid cavity is fully formed by the scapula and is the socket portion of the ball and socket joint of glenohumeral joint. But the glenoid cavity is very shallow and cover only one third to one fourth of the head of humerus. So to further deepen the cavity, the glenohumeral joint is guarded by a rim of the fibro cartilaginous structure called the glenoid labrum. It stabilises mainly the anterioinferior portion of the joint.