Rib

Any of the flat, curved bones that form a framework for the chest and a protective cage around the heart, lungs, and other underlying organs. There are 12 pairs of ribs, each joined at the back of the ribcage to a vertebra. The upper 7 pairs, known as “true ribs”, link directly to the sternum by flexible costal cartilage. The next 2 or 3 pairs of “false ribs” connect indirectly to the sternum by means of cartilage attached to the cartilage of the ribs above. Between and attached to the ribs are thin sheets of muscle ( intercostal muscles) that act during breathing. The spaces between the ribs also contain nerves and blood vessels.