Floating ribs are the eleventh and twelfth pair of ribs which are only connected to a person's backbone and not to the sternum. They're not even connected to other ribs, as the false ribs are. In some people, the tenth pair of ribs are also floating ribs.
The floating ribs are small and delicate, with the eleventh rib being bigger than the twelfth. They have pointed, cartilaginous tips.
The purpose of the ribcage is to protect vital internal organs, like the lungs and the heart, and to help a person breathe. Some biologists aren't quite sure what the function of the floating ribs are, but others believe they protect the kidneys.