Which divisions make up the pectoralis major muscle?

The division of the pectoralis major muscle consists of the clavicular, sternal, and costal fibers. This muscle is a large, fan-shaped muscle located in the upper chest and is primarily responsible for movements of the shoulder and arm.

The clavicular fibers originate from the clavicle and participate in flexion and adduction of the humerus. The sternal fibers originate from the sternum and ribs, contributing to the adduction and internal rotation of the arm. The costal fibers, which come from the lower ribs, enhance the actions of the sternal fibers and aid in adduction.

Understanding these divisions is essential for effectively designing exercise programs or rehabilitation strategies, as targeting specific areas can optimize muscle engagement and ensure balanced development of the upper body. Recognizing the multifaceted nature of the pectoralis major allows trainers and fitness professionals to tailor their approaches to meet individual client needs.