Definition for Glenoid cavity
From Biology Forums Dictionary
The glenoid cavity is a part of the shoulder. It is a shallow pyriform, articular surface, which is located on the lateral angle of the scapula. It is directed laterally and forward and articulates with the head of the humerus; it is broader below than above and its vertical diameter is the longest.
This cavity forms the glenohumeral joint along with the humerus. This type of joint is classified as a synovial, ball and socket joint.
The cavity surface is covered with cartilage in the fresh state; and its margins, slightly raised, give attachment to a fibrocartilaginous structure, the glenoid labrum, which deepens the cavity.
Compared to the acetabulum (hip-joint) the glenoid cavity is relatively shallow. This makes the shoulder joint prone to luxation. Strong ligaments and muscles prevents luxation in most cases.
By being so shallow the glenoid cavity allows the glenohumeral joint to have the greatest mobility of all joints in the body, allowing 120 degrees of unassisted flexion. This is also accomplished by the great mobility of the scapula (shoulder blade).