Fill in the Blanks Thoracic CageOnline version Fill in the Blank Activity - Bones in the Thoracic Cage by Morgan Cooper 1 vertebrae ribs elongated sternum thoracic cartilage not slender inferior false manubrium curved cage process xiphoid true costal 7 T5 10 shaft body T12 floating ribs 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 .