The skeleton of the thoracic cavity contains the sternum, ribs and thoracic vertebrae. There are 37 bones in the thorax, one sternum, 12 vertebrae and 24 ribs.
There are 12 ribs on each side of the body. Each rib contains a head, neck and shaft. The first rib is the shortest and more sharply curved than the others. Ribs one to seven are connected to the sternum by costal cartilages. These are called "true ribs." Ribs eight to 10, also known as "false ribs," are joined to the costal cartilage of the previous rib by their own costal cartilage. Ribs 11 and 12 are known as "floating ribs" because they are not attached in front.
The sternum consists of three parts: the manubrium, the body and the xiphoid process. The manubrium is the top of the sternum, and it connects to the clavicles and the first and second ribs. The manubriosternal joint, or sternal angle, is where the manubrium and body meet. The body is the longest part of the sternum and it is flat. It connects to ribs three to seven. The xiphoid process is the little pointed part at the bottom of the sternum and is an attachment point for several major muscles.
The 12 thoracic vertebrae increase in size from top to bottom. They are different from the other vertebrae in the human body because they contain facets where the ribs attach to them.