There are 12 ribs, which extend from the thoracic spine and wrap around the thoracic cavity to form the rib cage. Some attach to the sternum and enclose the rib cage, while others float with only one bony attachment point.
The ribs protect the organs inside the body and serve as an important attachment point for certain muscles. They are mostly fixed in place but have just enough movement and flexibility to allow for movement during breathing, rotating and stretching. When one inhales, the ribs expand to accommodate the inflated lungs. When one exhales, they move inward with the lungs.
Ribs are relatively small bones and can fracture easily during a fall.