Rib

Any one of the paired bones, 12 on either side, extending from the thoracic vertebrae toward the median line on the ventral aspect of the trunk. The long curved bones which form the rib cage. Generally, ribs 1 to 7 are connected to the sternum by their costal cartilages and are called true ribs, whereas ribs 8 to 12 are termed false ribs.

Source: NCI Thesaurus (C12782).