ribs that are not joined in front of the chest bone are breastbone.The sternum or breastbone is a long flat bonelocated in the center of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Shaped roughly like a necktie, it is one of the largest and longest flat bones of the body.