 This is Dr. Sanjay Sanyal, Professor Department Chair. This is going to be a demonstration of the entire diaphragm. I'm standing on the right side of the spine cadaver. The camera person is on the left side and we are focusing on the diaphragm after we have removed the endoabdominal fascia. So this is the right dome of the diaphragm. This is the left dome of the diaphragm. First, let's take a look at the muscles of the diaphragm. The muscles are the peripheral portion. Central portion is the central tendon of the diaphragm. We can see these muscle fibers here. These are the costal fibers which take origin from the ribs. And if you look very closely, we can see the fibers are going towards the central tendon. And here also we can see the same thing. We can see the fibers are all converging towards the central tendon. So these are the costal fibers. Antiremost fibers are referred to as the sternal fibers because they take origin from the inner surface of the sternum. And the posterior most fibers, if you were to take a close look, they are referred to as the lumbar fibers because they take origin from the lumbar vertebrae. So these are the lumbar fibers. Similarly on this side also, these fibers that we see here, these are the lumbar fibers. So therefore we have the sternal fibers, the majority, the costal fibers and the lumbar fibers. And all of them converge to the central tendon, which is shaped like a clover leaf. And when these muscles contract, they flatten the central tendon. And therefore they bring down the domes of the diaphragm. And that is how abdominal thoracic respiration takes place. Now let's take a look at some of the orifices. We can see the minor orifice anteriorly between the sternal fibers and the costal fibers. And that orifice is referred to as the sternocostal triangle or the antrolateral gap of lary. It is also referred to as the hiatus of morgagni. Coming through that, we can see this structure here. This is the superior epigastric artery, which is one of the terminal divisions of the internal thoracic artery. This is the superior epigastric on the left side. And we can see the superior epigastric on the right side also. Through this, really, they can be a hernia. And that is known as a hernia of morgagni. Now if you were to take a look at the posterior aspect, especially on the left side, we can see another area between the costal fibers here and the lumbar fibers here, this triangular portion. This is more prominent and more obvious on the left side. It is hardly visible on the right side because of the liver. This is called lumbocostal trigone or the lumbocostal triangle. This is a potential area of weakness, especially on the left side. In this area, as you can see in this dissection, there is no muscle. Therefore, it is covered only by the endobdominal fascia from the abdominal side and by the endothoracic fascia from the thoracic side. And therefore, the trauma to the abdomen and the thorax can produce rupture of this area and can push the abdominal contents into the thorax. And that is known as a traumatic diaphragmatic hernia. This is also a site of defect in some new bonds. And this is referred to as the foramen of boctalic. And if the defect persists after birth, it can produce a congenital diaphragmatic hernia, which is known as the hernia of boctalic. And these babies are usually stillborn. All the intestinal contents are found on the left side of the chest and all the medial stillness and other contents are pushed to the right side of the chest. So that is another area of weakness and a potential site of herniation. This is a plain history of the domain of a baby stillborn with the congenital diaphragmatic hernia. Now let's take a look at the major orifices. We can see this orifice here. This is the cable hiatus, which is at the level of T8 in the central tendon to the right of the midline. And this thing that we can see here is the highly thrombosed inferior vena cava. That's why it is called the cable hiatus. The other end of the inferior vena cava is this one here, which we have cut. So this portion of the inferior vena cava was inside the liver. Also passing through the cable hiatus is the right phrenic nerve and the lymphatics, which go from the bare area of the liver into the thorax. The next orifice that we can see here is this orifice. This is the esophageal hiatus, which is at the level of T10 to the slightly to the left of the midline. And we can see these are figures is coming out. This is the abdominal segment of these are figures, which is approximately half an inch and we have pulled it down. Apart from these are figures, we can see this nerve and this nerve. These are the anterior and the posterior vagus, respectively. In the thorax, the vagus is left and right. But as it comes down below the hilum of the lung, the left vagus becomes anterior and the right vagus becomes posterior. And that is the way they come out through the esophageal hiatus. Apart from that, we can see this artery here. This is the esophageal branch of the left gastric artery coming from the celiac trunk. And it is accompanied by the vein, which drains into the portal vein. So these are the structures which pump through the esophageal hiatus. This portion of the esophagus is the site of portosystemic anastomosis, cirrhosis with portal hypertension. Esophageal branch of the left gastric vein can form esophageal varices. Esophageal hiatus is very unique. And if you go to take a close look, you'll find that it is formed by the fibres of the right crust of the diaphragm. So these are the fibres of the right crust of the diaphragm. These fibres, they go all the way around the esophageal hiatus and I'm tracing it. And they come back again, and they're coming down and they meet. So this whole thing is the right crust fibres and they split to form the esophageal hiatus. These splitting fibres of the right crust of the diaphragm, they act as a pinch cock mechanism and they constitute the lower esophageal sphincter. And also attached to the right crust of the diaphragm, but not visible in this dissection, will be the suspensory ligament of trites, which suspends the teodonticinal flexure. Then we have the next orifice, which is this one here, where my instrument is located. This is the aortic hiatus. This is located at the level of T12 and we can see the aorta is passing through that. This is formed by, severely it is formed by the median archaeate ligament here. And on either side, on the right side, this is the right crust of the diaphragm, which extends from L1 to L3. And on the left side, it is formed by the left crust of the diaphragm, which extends from L1 to L2. So therefore the median archaeate ligament bridges in front of the aorta and forms the aortic hiatus. And we can see the aorta is coming through that. Apart from the aorta, what are the structure passes through this? From right to left, we have the azygous vein, which we cannot see here, and the thoracic duct, which also we cannot see here. So these are the structures which pass through the aortic hiatus. So we have seen the three important hiatus with their structures. Now let me mention the ligaments of the diaphragm. For that, we'll come to the right side. The median archaeate ligament I have already described, which bridges in front of the aorta to form the aortic hiatus. Now if we were to look laterally, we can see and in a structure here, bridging over the soas major muscle. This is medial archaeate ligament, which is the upper limit of the soas fascia. The diaphragm takes attachment from there also. When we go further laterally, we can see yet another ligament structure here. This is the lateral archaeate ligament, which is the upper free margin of the quadratus lumborum sheath. So therefore, the diaphragm takes origin from the median archaeate ligament, which is this one here. It takes origin from the medial archaeate ligament bridging over the soas major and it takes origin from the lateral archaeate ligament bridging over the quadratus lumborum. And the same thing can be seen on the left side also. And here we can see it even more clearly. This is the median archaeate ligament on the left side bridging over the soas major. And this is the lateral archaeate ligament bridging over the quadratus lumborum. So these are the ligaments of the diaphragm. The diaphragm is supplied by the phrenic nerve. The phrenic nerve is C345, which is both sensory and motor. The muscular component of the diaphragm, which extends further posteriorly down, is supplied by motor component of the phrenic nerve. The sensory component supplies sensation to the central portion of the diaphragm. What about sensory of the peripheral parts of the diaphragm? They are not supplied by the phrenic nerve. They are supplied by the lower six intercostal nerves. Coming to the visible blood vessels of the diaphragm, we can see this blood vessel on the inner surface. This is the left inferior phrenic artery and similarly we can see the blood vessels here on the right. This is the right side inferior phrenic artery. Both of these come from the abdominal aorta. They are the first branches of the abdominal aorta. Additionally, the diaphragm is also supplied by superior phrenic artery, which also come from the aorta. Finally, before we conclude, as I mentioned, the diaphragm extends more posteriorly than anteriorly. And therefore the diaphragm forms the posterior wall of the abdomen as well as it forms the bed of many of the abdominal organs, most notably the kidneys. This is the left kidney. This is the right kidney. That's all for now. Thank you very much for watching. Dr. Sanjay Sanyal signing out. Mr. Kendal Kambabaj, the camera person. If you have any questions or comments, please put them in the comment section below. Have a nice day.