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- Use of this artwork requires proper credit to be given (Permission: Dr. Joe Muscolino. www.learnmuscles.com – art work Giovanni Rimasti)
The Pectoralis Major is composed of two heads: Sternocostal head and Clavicular head.
- The pectoralis major attaches from the medial clavicle, sternum, and the costal cartilages of ribs #1-7 to the lateral lip of the bicipital groove of the humerus.
- Adducts the arm at the glenohumeral joint (entire muscle)
- Medially rotates the arm at the glenohumeral joint (entire muscle)
- Flexes the arm at the glenohumeral joint (clavicular head)
- Extends the arm at the glenohumeral joint (sternocostal head – from a position that is flexed beyond anatomic position)
- Horizontally flexes the arm at the glenohumeral joint (entire muscle)
- Protracts the shoulder girdle (acting through the humeral attachment) at the scapulocostal joint and sternoclavicular joints (entire muscle)
- The pectoralis major comprises the vast majority of the anterior axillary fold of tissue.
- There is a twist in the fibers of the sternocostal head of the pectoralis major.