Axial Skeleton

The Bony Thorax

The Bony Thorax

• Includes sternum, ribs, and thoracic vertebrae

• Cage protects heart, lungs, and major blood vessels

The Bony Thorax - 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

The Bony Thorax - Sternum

The Bony Thorax - 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

The Bony Thorax - Ribs