"The Cause" (part 1 of 3)

Most people think that the shoulder is a ball and socket connection much like the hip joint; nothing could be further from the truth. The shoulder is made up of two main bones the humerus the large bone in the upper arm, and the scapula the fan shaped bone of the upper back. The humerus is covered by cartilage which in a cartilage covered semi cup called the glenoid. This and the top boney extensions of the scapula make up a very fragile ball joint.

When its time to evaluate the shoulder muscles, most people we think of the shoulder muscles we think of the deltoids, and the trapezius. However the shoulder is made up of other lesser seen muscles whose development is essential to health shoulder joints. These lesser muscles are the Supraspinatus, Infraspinatus and the teres major, minor better know as the rotor cuff muscles. Below is the action of these muscles, there purpose, origin and insertions: