Fill in the Blanks Thoracic CageOnline version Fill in the Blank Activity - Bones in the Thoracic Cage by Morgan Cooper 1 manubrium true body sternum ribs cage T5 slender vertebrae process 10 thoracic false costal floating inferior 7 not curved cartilage ribs shaft T12 xiphoid elongated The protects the heart and lungs . It consists of 12 thoracic , twelve pairs of , and . The sternum is an bone and consists of the , which is the superior sternal bone . The or middle sternal bone extends from the - T9 . The is the sternal bone . The 12 pairs of articulate posteriorly with the T1 - thoracic vertebrae . Ribs 1 - attach to the sternum through are known as ribs . Ribs 8 - are known as ribs . Ribs 11 - 12 that do attach to the sternum are know as ribs . The 1st rib is short , broad , and . The 6th rib has a head , neck and . The 12th rib is a short bone .