False ribs

The five lower pairs of ribs are called false ribs because they do not connect to the sternum directly. The eighth, ninth and tenth pairs of ribs attach to the sternum indirectly via the costal cartilages of the ribs above them. The elasticity of the costal cartilages allows ribcage movement for respiratory activity. The eleventh and twelfth pairs of ribs to not attach to the sternum at all and are usually called floating ribs.