Final answer:
The shoulder girdle is composed of the shoulder blade (scapula) and the collarbone (clavicle), which attach the upper limbs to the body.
Step-by-step explanation:
The structures that form parts of the shoulder girdle are the shoulder blade (scapula) and the collarbone (clavicle). The shoulder girdle, also known as the pectoral girdle, is responsible for attaching the upper limbs to the trunk of the body. Its connection to the axial skeleton is through muscles alone, providing a wide range of motion. This anatomical structure includes two bones on each side, the scapula, which is a pear-shaped flat bone helping to form the shoulder joint, and the clavicle, a long bone that acts as a strut between the shoulder blade and the sternum.