Final answer:
The clavicles are S-shaped bones that serve to position the arms and articulate with the sternum and scapula. The scapula is part of the pectoral girdle, providing structural support and location for radiographic analysis, significant in medical diagnoses such as detecting lung cancer.
Step-by-step explanation:
The clavicles are long, S-shaped bones that serve a critical function in the musculoskeletal system by positioning the arms on the body and providing structural support. They extend horizontally across the front of the thorax, just above the first rib, and are susceptible to fractures, especially from falls where the arms are outstretched, transmitting force that may exceed their resistance. The clavicle articulates with the sternum and the scapula, with the latter being an essential part of the pectoral girdle located on the posterior side of the shoulder. It does not articulate with the ribs due to being surrounded by muscles.
The scapulae play an integral role in anchoring the upper limb to the body, while also contributing to the lung field in radiographic imaging. An anteroposterior radiograph can show indications of various medical conditions, such as pulmonary infiltrates or caving formations, which could suggest abnormalities like lung cancer.