manubrium floating true false body thoracic 7th xiphoid 11 ribs costal 8 cartilage 10 cage superior 12 7 middle 1 sternum inferior process
The is composed of quite a few parts . First is the , which is an elongated flat bone forming the middle part of the anterior thoracic wall . It is composed of three parts , the ( which is the portion ) , ( the portion ) , and ( the portion ) . The are also a part of this cage , - attach anteriorly to the sternum through strips of and are known as ribs . - are ribs that only attach to the cartilage . - do not attach to anything are known as ribs .