The major pectoral, or pectoralis major, is a large, fan-shaped muscle located in the upper chest. It plays a crucial role in the movement of the shoulder joint, allowing for actions such as pushing, lifting, and rotating the arm. This muscle is divided into two parts: the clavicular head, which originates from the collarbone, and the sternal head, which originates from the sternum. The pectoralis major is essential for various physical activities and is often targeted in strength training exercises like bench presses and push-ups. Strengthening this muscle can improve upper body strength and enhance athletic performance.