Chest bones. Historical artwork of the bones of the human chest. The breastbone (upper centre) at the front of the chest supports 12 pairs of ribs that circle the chest and connect to the backbone (down centre). The backbone is a flexible column of 26 spinal bones (vertebrae, not all seen here) supporting the body and protecting the spinal cord. The ribs form a protective cage around the heart and lungs (not seen). The collar bones (clavicles) run across the top of the ribcage and articulate with the arm bones (not seen) as do the scapula bones (shoulder blades) of the back.