The axial skeleton - the rib cage
The human skeleton has 12 pairs of ribs. These form a protective cage - the rib cage - that surrounds the thoracic cavity in which the heart and lungs lie.
The ribs are attached at the back to the thoracic vertebrae. The top ten pairs of ribs are attached at the front to the sternum (or breast bone) - a flat bone running down the front of the chest. The two bottoms pairs of ribs are free at the front.
