The rib cage [thorax] serves among other things as a flexible frame work for the transmission of the respiratory muscles power and protects the lungs. It consists of:
12 thoracic vertebrae,
rib pairs including rib cartilages and
the breast bone.
The "pillar" of the rib cage is the spine. The ribs are attached to the spine by flexible connections. The front of the breastbone is kept flexible by cartilage. This way, the rib cage can expand and contract during respiration. The movement of each rib ressembles that of a bucket handle and the moving breastbone ressembles a water pump.
Did you know?
The amount of air that you are able to breath ("How much?"; equivalent to "How fast can I walk with it ?") does not only depend on the "state" of the lungs but also, significantly, on the movement range of the rib cage's. The state of the respiratory muscles and the position of shoulder blades and collarbone play a decisive role in this process. In the long run it is important how easily the rib cage can be moved.
