Final answer:
Ribs 8-12 are called false ribs or vertebrochondral ribs. Ribs 8-10 have their costal cartilages attached to the cartilage of the next higher rib, while ribs 11-12 are floating ribs that do not attach to the sternum or to another rib.
Step-by-step explanation:
Ribs 8-12 are called false ribs or vertebrochondral ribs. The costal cartilages from these ribs do not attach directly to the sternum. Instead, the costal cartilages of ribs 8-10 are attached to the cartilage of the next higher rib. Lastly, ribs 11-12 are known as floating ribs or vertebral ribs and do not attach to the sternum or to another rib.