 So now we're going to talk about the thoracic cage, which consists of the sternum, the costal cartilage, the ribs, and then the thoracic vertebrae which are going to connect to all of the ribs. Looking at the sternum here, the sternum consists basically of three major parts. This upper part is called the manubrium. Then we have this middle part here called the body, also called the gladiolus. And then we have this part here called the xiphoid process, which starts off as kind of a soft cartilage, but then later on it's going to change to bone tissue. Now looking here at the manubrium, some features to point out is there's a notch here. This is oftentimes a landmark that certain medical professionals would have to know. Then you'll notice that there's this border right here between the manubrium and then the body. And this is actually kind of a ridge that you could easily feel. And you'll notice that this is a convenient way to count ribs because you'll notice that the second rib actually connects, its costal cartilage connects right there. Then we once again point out the xiphoid process. And one of the things about the xiphoid process is if you don't place your hand position just correctly in CPR, then you can actually break the xiphoid process off and it could hit the liver or damage the liver. And you certainly don't want to do that. Now connecting the ribs to the sternum is the costal cartilage. And then you have the ribs and there are actually 12 pairs of ribs. And we can break these down into three major groupings. The first seven pairs, one, two, three, four, five, six, seven, if you look at them have their costal cartilages directly attached to the sternum. These are called the vertebrosternal ribs. These are also commonly referred to as the true ribs. With the pairs 8, 9, and 10, their costal cartilage is actually attached to the costal cartilage of rib number seven. So notice that it is indirectly but not directly connected to the sternum. And so rib pairs 8, 9, and 10 are called vertebral chondral ribs. And then rib pairs 11 and 12 have no costal cartilage associated with them and they are called vertebral ribs. These are also called floating ribs, although as you can see they're actually not floating. So that essentially is the thoracic cage.