The thoracic cage is a bony case consisting of ribs and sternum which encases vital organs like the lungs and the heart and shapes the chest.
There are 12 pairs of ribs in the body. They are attached to the vertebral column with most of the ribs anteriorly joining to the sternum bone via costal cartilage.
The first seven ribs directly attach to the sternum (true ribs), whereas the following three ribs only attach to the costal cartilage of the true ribs.
Finally, the last two pairs have no anterior attachment and are only connected to the vertebral column posteriorly. They are called floating ribs.
The thoracic cage is rigid to provide protection for the organs of the thorax, but are still susceptible to subtle elevation and depression movements produced by thoracic muscles. This allows the expansion of the lungs during breathing.
Learn more about the anatomy of the thoracic cage using our interactive diagrams below, or test your knowledge with advanced anatomy quizzes.