Costal cartilage is a type of hyaline cartilage. It is a flexible, white connective tissue that serves to prolong the ribs forward and contributes to the elasticity of the walls of the thorax. The first seven pairs of costal cartilage are connected with the sternum, the next three are each articulated with the lower border of the cartilage of the preceding rib, and the last two have pointed extremities, which end in the wall of the abdomen. The costal cartilages vary in their length, breadth, and direction, and they increase in length from the first to the seventh, then gradually decrease to the twelfth.