The sternum is a flat bone that makes up the front wall of the chest. The sternum consists of three elements: the handle of the sternum (manubrium sterni), which takes the shape of a quadrangular flat bone; the body of the sternum (corpus sterni), which resembles a rectangle, to the side surface of which ribs two to six are attached; and the last part of the sternum is the xiphoid process (processus xiphoideus), which is usually cartilage (therefore, it is rarely preserved in the bone material). The sternum is made of a thin layer of compact matter that surrounds the spongy part containing the bone marrow.