Sternum
flat bone in the middle front part of the rib cage / From Wikipedia, the free encyclopedia
The sternum or breastbone, in vertebrate anatomy, is a flat bone. In amphibians and reptiles it is normally shaped like a shield, often made of cartilage. It is absent in both turtles and snakes. In birds it is larger, and has large flight muscles attached to it.[1] Only in mammals does the sternum take on the longer form seen in humans.