 Good day everybody. This is Dr. Sajya Sanyal, Professor, Department Chair. So this is the dissection of the cadaver. This is the supine cadaver. I'm standing on the right side. Camera person is on the right side. This is the head end. This is the foot end. So we were dissecting the chest wall and in the process, first we had to dissect out the muscles in front of the chest wall. So what you see here in front of you, this is the pectoralis major, which I'm outlining with my finger right now. And this muscle that you see here this is the deltoid muscle. This groove that you see, which I have highly exaggerated, this is the deltoid pectoral groove and running in this will be the cephalic vein, which in this particular cadaver is highly atrophied. Let's come to the pectoralis major muscle. You can see these muscle fibers. This is the sternocostal head. It is taking origin from the sternum ribs and this is the abdominal part of the sternocostal head and I've cut it from here and this is the clavicular head. It was taking origin from the clavicular. I'm going to lift this up now. As I told you, it's very thin and atrophied in this particular cadaver and you can see the fibers, the clavicular fibers are superficial. The sternocostal fibers are deep. They twist and they get inserted onto the lateral lip of the inter tubercular sulcus here. Now let me turn this and when I turn this we can see the next muscle underneath. This is the pectoralis minor. Normally it's supposed to take origin from the third, fourth and fifth costal cartilages, but in this particular cadaver it is taking origin from the third and the fourth. It's also highly atrophied and I'm lifting that up also. In the process, I will draw your attention to two sets of neurovascular bundles. One is this one here that you see. This is the continuation of the cephalic vein, which is piercing through the costa-corogate membrane and it will go into the axilla and drain to the axillary vein. These neurovascular bundles that you see here, this is the lateral pectoral nerve. You can see they're supplying the pectoralis major from the deep surface and this structure that you see here, this is the medial pectoral nerve. It supplies the pectoralis minor and then it supplies the pectoralis major. So we are seeing basically the inner surface of the pectoralis major and the pectoralis minor. I'm going to reflect that also. Once I reflect it, now we can see the muscles of the chest wall. These muscle fibers that you see here, these are the combination of external and internal intercostal muscle. We cannot differentiate them because, as I said, the fibers are highly atrophied. However, we can draw some conclusions. So this is the external intercostal muscle and if you trace them further medially, you find that they become membranous. That is the continuation of the external intercostal muscle, which is called the external intercostal membrane. And deep to that, we have the internal intercostal, some of which fibers we can see. We can see this is the internal, control part of the internal intercostal and further laterally will be the nauseous part of the internal intercostal. So these are the muscle fibers. She's got an extremely thin chest wall. So we can see this is the rib here. This is the interosseous part of the rib and this is the cartilaginous part of the rib. We can see it makes a sharp bend here. That is the reason why the portion of the muscle which is between the bony portion, they are responsible for depression of the ribs in the case of internal intercostal. And the intercontral part, they are responsible for elevation of the ribs because they follow the curvature of the ribs. And finally, we have not dissected extensively because most of the structures are highly atrophied here. If you trace it, you find that this is the costal margin. And this costal margin, she's got a very narrow costal angle. This is the sternum. This is the clavicle. So under the clavicle, this is the first rib. But we cannot feel the first rib when all these muscles are in place. So here we can feel it, but normal person we cannot feel it. So therefore, we can feel the sternal angle of Louie here. And tracing from the sternal angle of Louie, if you trace laterally, you can see this is the second rib. So therefore, this is the second intercostal space. This is the third intercostal space. The fourth intercostal space, the fifth, sixth, and seventh intercostal space, costal margin. This is the subcostal angle. So these are the structures which we can see in this preliminary dissection. And before I conclude, since we have already opened, I would like to draw your attention to something else. You see a structure here, which I have lifted up with my hand here. This is intercostal brachial nerve. This is intercostal brachial nerve. And this is coming. It's supplying the chest wall and it's supplying the arm also. So these are the structures which I wanted to show you. Thank you very much for watching, ladies and gentlemen. Have a nice day.