What is the proximal attachment of the pectoralis major muscle?

The pectoralis major muscle is primarily responsible for movements of the shoulder joint, including flexion, adduction, and internal rotation of the arm. Its proximal attachment is multifaceted, encompassing the sternal end of the clavicle and the sternum. This extensive attachment allows the muscle to exert force efficiently during arm movement and contributes significantly to the strength and functionality of the shoulder girdle.

The sternal end of the clavicle provides stability and support, while the attachment to the sternum offers a broader range of motion and power during shoulder flexion and adduction. Additionally, pectoralis major's connection to the ribs through the costal cartilages aids in respiration and further enhances the muscle's functional role. Thus, option B accurately represents the proximal attachment of the pectoralis major muscle, integrating its anatomical structure with its functional capabilities in the upper body.