The ribs partially enclose and protect the chest cavity, where many vital organs (including the heart and the lungs) are located. The rib cage is collectively made up of long, curved individual bones with joint-connections to the spinal vertebrae. At the chest, many rib bones connect to the sternum via costal cartilage, segments of hyaline cartilage that allow the rib cage to expand during respiration. Although fixed into place, these ribs do allow for some outward movement, and this helps stabilize the chest during inhalation and exhalation. The human rib cage is made up of 12 paired rib bones; each are symmetrically paired on a right and left side. Of all 24 ribs, the first seven pairs are often labeled as 'true.' These bones are connected to the costal cartilage, while the five other 'false' sets are not. Three of those connect to non-costal cartilage, and two are deemed to be 'floating,' which means they only connect to the spine. While there are some cases of minor anatomical variation, men and women generally have the same amount of ribs. A differing rib count between the genders is largely a medical myth.