Separate bones and cartilages are connected to each other through joints and cartilages, partly synarthrosis and partly diarthros, to form the rib cage. The abundance of bones and joints and the fact that some parts of the ribs are made of cartilage tissue provide the rib cage with the opportunity to easily change its volume and at the same time the elasticity of its walls.The fact that the ribs and sternum are made of light bone tissue, the thinness of the ribs and their spaced arrangement ensure the lightness of the walls. These features of the chest walls are very important for the function of the chest cavity. We can activate the light walls by working less muscles and consuming less energy. By pulling the muscles while breathing. We can also put it into action. The chest cavity, which expands with the effect of the pulling force of the muscles while breathing, returns to its previous state and shrinks spontaneously, without the need for other muscles to work, thanks to the elasticity of its walls, as the effect of the muscles disappears. For this reason, the rib cage is responsible for protecting the important organs in the chest cavitn