Anatomy Chart courtesy of FCIT
The Pecs attach to the humerus near the shoulder joint and originate on the breastbone in the center of the chest.
The fibers of the Pectoralis muscles run like a fan across the chest. The fan-like structure of the Pecs allows the humerus to move in a variety of planes across the body.
The Pectoralis Minor muscle (not shown in the diagram) is located underneath the pectoralis major muscle, attaching to the coracoid process of the scapula and originating on the middle ribs.
