The lower five pairs of |ribs| are called |false ribs|, because they do not directly articulate with the |sternum|. Instead, the eighth, ninth, and tenth |ribs| are joined to the seventh |rib| by cartilaginous tissue. The eleventh and twelfth pairs of |ribs| (the last two pairs of |false ribs|) are also called floating |ribs|, because they do not connect anteriorly to any other |rib| or the |sternum|.