Which bones constitute the pectoral girdle?

The pectoral girdle is primarily composed of the clavicle and the scapula, which work together to connect the upper limb to the trunk of the body. The clavicle, or collarbone, serves as a strut that stabilizes the shoulder and provides attachment points for muscles. It also connects to the sternum at one end and to the acromion of the scapula at the other.

The scapula, commonly known as the shoulder blade, is a flat, triangular bone that provides a surface for muscle attachment, enabling a wide range of motion in the shoulder. It articulates with the humerus at the shoulder joint, allowing for upper limb mobility.

By understanding the structure and function of the pectoral girdle, it becomes clear why the correct answer includes both the clavicle and the scapula, as they are essential components in supporting and facilitating the movement of the arm.