Shoulder Joint AnatomyLet’s talk about shoulder joint anatomy. As we briefly discussed on the introductory page, it is a ball and socket joint configuration. The humeral head is the “ball" and the glenoid is the “socket”. Other structures that serve to make up the “shoulder girdle” include the clavicle (collar bone), the acromion (top part of the scapula, or, shoulder blade) and the coracoids process (part of the front portion of the glenoid and an attachment point for ligaments). What sets the shoulder joint apart from other ball and socket joints, such as the hip, is mainly that the glenoid (socket) is rather shallow and does not, by itself, contribute too much to stability. It also relies upon the integrity of such structures as muscles, tendons and ligaments to maintain that stability and to keep it “in joint”.
The picture above shows some shoulder structures as seen from the front.
This view, from behind, shows more of the muscles and tendon structures that make up the rotator cuff complex, namely the supraspinatus, infraspinatus, and teres tendons. It also shows the sub-acromial bursa sac, which has a reputation for being a troublesome character. This bursa can become severely inflammed adnd restrict motion when part of a condition called shoulder impingement. Looking at these pictures, you can see the structures and how they are located either in the front, or the rear of the shoulder. You can also see how the combination of these muscles, tendons and ligaments work together to not only stabilize the joint, but to provide a wide range of functions and movements.
The glenoid (socket) is, by nature, quite shallow, so a structure surrounds it, called the glenoid labrum, which acts to help “deepen” the socket to increase stability. This labrum is the source for several types of injuries that can affect shoulder stability, such as the labral tear, and a condition known as the S.L.A.P. tear. More on that later... Leave Shoulder Joint Anatomy; return to Shoulder Pain
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