The major bony components of the thorax are the sternum, thoracic vertebrae and ribs. These bony components are in conjunction with intervertebral discs and costal cartilage.
The top of the thorax contains the sternum, which can also be referred to as the breastbone. This is a flat bone that helps to protect the rest of the thorax. It is a long, sword shaped bone with a piece of cartilage on the end called the xiphoid process. It is located in between the two collarbones.
Thoracic vertebrae are similar to the lumbar vertebrae that are located in the back. There are 12 vertebrae in the thoracic system. They work together with the sternum to hold the ribs into place and are there for the protection of the organs that are in the ribcage system. The way these vertebrae articulate, or move, is important to the way that the ribs move.
There are 12 ribs in the thorax. They are resilient and lightweight, making them ideal for the organ protection they provide. There are true ribs, false ribs and floating ribs. True ribs are connected to the sternum with costal cartilage. False ribs are only attached to other ribs and do not ever directly touch the sternum. Floating ribs are only connected to the thoracic vertebrae and "float" in the thorax area.