The glenoid cavity of the scapula is also known as the "glenoid fossa", which is not surprising because in the context of features and markings on bones a fossa is "a shallow depression" and such depressions in the surface of bones often receive another articulating bone with which a joint is formed.
The glenoid cavity of the scapula (shoulder bone) articulates with the head of the humerus (upper-arm bone) at the shoulder joint, enabling the arm to move relative to the torso. |
The glenoid cavity is slightly concave from above downwards and from side to side.
It is shallow and a site of attachment of the glenoid labrum (also known as the glenoid ligament), which forms a fibrocartilaginous rim around the glenoid cavity.
The glenoid labrum is important because it has the effect of deepening the socket into which the head of the humerus (bone) rests, forming the shoulder joint.
Further explanation:
The shoulder joint is classified as a a 'ball and socket' joint.
However, in this case the 'socket' part formed by the glenoid cavity of the scapula is relatively small and shallow, covering, at most, only about a third of the 'ball' part of the joint which is formed by the head of the humerus. The socket of the shoulder joint is deepened by the fibrocartilage tissue called the glenoidal labrum that is located around the rim of the glenoid cavity. (The glenoid labrum is approx triangular in section, its base being attached to the circumference of the glenoid cavity. It extends into the tendon of the long head of the biceps brachii, which attaches to it via two fasciculi that blend with the fibrous tissue of the glenoid labrum.) |
