The thoracic cage or the rib cage protects both the heart and lungs. The thoracic cage is composed of 12 pairs of ribs, the sternum and 12 thoracic vertebrae.
The 12 pairs of ribs are further subdivided into groups that include true, false and floating ribs. The true ribs are the top seven pair of ribs, and the rib pairs numbered eight through 10 are the false ribs. The floating ribs are the 11th and 12th rib pairs. They are called floating ribs because they are solely connected to the thoracic vertebrae.
All ribs are connected to the thoracic vertebrae, which is located at the back. True ribs are also connected to the sternum by a rib's coastal cartilage. However, false ribs are connected solely to a coastal cartilage and not to the sternum. Besides serving as protection for the heart and lungs, the ribcage is also important for the body's support and respiratory function.