GLOSSARY

The ribs are twelve pairs of curved, flat bones forming the side walls of the thoracic cage; all ribs articulate behind with the thoracic vertebrae.

Classification

• True ribs: ribs 1 to 7, attached directly to the sternum by their own costal cartilages.
• False ribs: ribs 8 to 10, whose cartilages join the cartilage of the rib above, forming the costal margin.
• Floating ribs: ribs 11 and 12, which have no anterior attachment.

Structure

Each rib has a head, neck, tubercle, and shaft; along the inner surface of its lower border lies the costal groove