The axial skeleton includes the sternum, ribs, and thoracic vertebrae that form the bony thorax. The sternum is formed by fusion of the manubrium, body, and xiphoid process bones. The twelve pairs of ribs are divided into true ribs attached to the sternum and false ribs either attached to other ribs or floating. Together these bones protect the heart, lungs, and major blood vessels in the thoracic cage.

1. Axial Skeleton The Bony Thorax

2. TheBonyThorax Includes sternum, ribs, and thoracic vertebrae Cage protects heart, lungs, and major blood vessels

3. TheBonyThorax - Sternum Formed by fusion of three bones Manubrium is top heart-shaped structure, includes jugular notch Body is middle elongated bone, fused with manubrium at Sternal Angle Xiphoid Process is inferior tip, fused with body at Xiphisternal Joint

4. TheBonyThorax - Sternum

5. TheBonyThorax - Ribs Twelve pairs of ribs form walls of thoracic cage Two sections of ribs: True ribs: first seven pairs, attached directly to sternum by costal cartilage False ribs: next five pairs either attached to cartilage of superior ribs or not attached anteriorly(two pairs called floating ribs) Intercostal spaces: between ribs, filled with muscles to aid in breathing

6. TheBonyThorax - Ribs