The sternum, or breastbone, is a flat bone at the front center of the chest. The ribs and sternum make up what is called the "ribcage." The ribcage protects the lungs, blood vessels, and heart, along with parts of the spleen, stomach, and kidneys from traumatic injury. The sternum is attached to the first seven ribs and also to the clavicle, or collarbone. The sternum is made up of three parts called the manubrim, the body, and the xiphoid process. In adults, the sternum portions are fused. The top of the sternum is the manubrim, or handle. It is connected to the first two ribs and is not completely rigid. The body, also called the blade or gladiolus, is right in the middle of the sternum. It connects to the third through seventh ribs directly and the eighth through tenth ribs indirectly. The xiphoid process is the bottom tip of the sternum. Rib pairs one through seven are called "true ribs" because they connect directly to the sternum with costal cartilage, which are segments of cartilage that help the chest cavity expand during respiration. Rib pairs eight through ten are called "false ribs" because instead of being directly connected to the sternum, they are connected to the seventh rib.