What is the origin of the sternal head of the pectoralis major?

The sternal head of the pectoralis major originates from the sternum and typically the costal cartilages of the second to sixth ribs. This anatomical origin is essential for understanding the muscle's function and its role in upper body movements such as adduction and internal rotation of the humerus. The fibers of the sternal head blend with the clavicular head and insert into the humerus, contributing to the powerful movements of the shoulder. Recognizing the specific ribs involved in this origin helps in diagnosing potential injuries in this region and helps to tailor rehabilitation programs for athletes or individuals with shoulder issues.