What is the primary function of the pectoralis muscles?

The primary function of the pectoralis muscles is the movement of the arms. The pectoralis major and pectoralis minor are the two main muscles in this group, and they play a crucial role in shoulder movement. These muscles are responsible for actions such as flexion, adduction, and medial rotation of the arm. For instance, when you raise your arms to the front or bring them closer to your body, it is largely the pectoralis major that facilitates this movement. Their attachment to the sternum and the clavicle also enables them to assist in stabilizing the shoulder joint during various upper body activities. Thus, their key role is indeed in facilitating a wide range of arm movements, making them essential for activities involving pushing or lifting with the arms.