What is difference between Floating and Fixed ribs

_{Humans have 12 pairs of ribs and each of them is attached to the spine. Among these 12 pairs 7 pairs are attached to the sternum or breast bone and the 3 pairs after that are connected to the part of the ribs just above them, these are fixed ribs. The last 2 pairs of ribs are only connected to the spine and have no attachment in the front. These last 2 pairs are called floating ribs.}