Final answer:
The statement is true; ribs and the sternum are considered flat bones because they provide protection for the organs and a surface for muscle attachment. They contribute to the protective thoracic cage, with the ribs curving around the organs they safeguard and attaching to the sternum at the front.
Step-by-step explanation:
The statement that ribs and sternum are classified as flat bones because they are thin and broad is True. Flat bones like the sternum and ribs are deemed so because they serve a protective function and offer a wide surface area for muscle attachment. The ribs, specifically, are curved, flat bones that contribute to the thoracic cage, protecting vital organs such as the lungs and the heart, and they connect to the sternum via costal cartilages.
The sternum, also referred to as the breastbone, is a long, flat bone present at the front of the chest, which along with the ribs forms the ribcage. This structure is not just flat; it is also slightly curved to contour with the shape of the body. Both the sternum and the ribs are essential for protecting critical organs and providing attachment points for muscles.
Additionally, ribs are categorized based on their attachment to the sternum. True ribs attach directly to the sternum, while false ribs have indirect or no sternum attachment, and floating ribs do not attach at all. The ribs articulate with the thoracic vertebrae at the back and are mostly attached to the sternum at the front via their costal cartilages, though the last two pairs of ribs are known as floating ribs because they do not attach to the sternum.