What are the three main bones that make up the shoulder?

The three main bones that compose the shoulder are the clavicle, humerus, and scapula. The clavicle, commonly referred to as the collarbone, serves as a support structure connecting the arm to the body, playing a critical role in shoulder stability. The scapula, or shoulder blade, provides attachment points for numerous muscles that facilitate shoulder movement. Finally, the humerus is the long bone of the upper arm that articulates with the scapula at the shoulder joint, allowing a wide range of motion. This combination of bones is essential for the overall function and mobility of the shoulder joint, making it a complex and important area for movement.

Other combinations provided in the options do not contain the correct set of bones that specifically function as the structure of the shoulder joint. The radius and ulna are bones of the forearm, while the sternum is part of the chest, and the femur is the thigh bone, both of which do not contribute to the shoulder's anatomy. The vertebrae and pelvis also belong to different parts of the skeletal system, further distancing them from directly relating to shoulder structure.