 Good day everybody. This is Dr. Sanjay Sanyal, Professor, Department Chair. So this is going to be the section of the anti-abdominal wall muscles. So, we have completely dissected out the structures from the anti-abdominal wall and we have dissected out the muscle layers. Before that, this is a supine cadaver. I am standing on the right side. My assistant one is on my right side, another is on the left side and the camera person is also on the right side. So this is the head end, this is the foot end. This is the right side, that is the left side of the cadaver. So, let's start. This first layer that we see here, which we have dissected out from here. This is the anterior supine, this is the iliac crest. So therefore, you have already guessed it, this is the external oblique muscle and my assistant is going to hold it with an artery forceps and as I lift it up, you can see that this is the aponeurosis of the external oblique. Now, the external oblique muscle fibers, if you notice carefully, the fibers are directed downwards and forwards and medially. Medially, it becomes aponeurotic and forms an anterior layer rectus sheath. Lower down, it gets inserted onto the outer lip of the iliac crest and it also forms the inguinal ligament, which you can see very clearly here. I am tracing the inguinal ligament here. You can see it is changed from the anterior supine to the pubic tubercle. So this is the inguinal ligament and let me lift it up for you. So therefore, this is the external oblique muscle and aponeurosis. Okay, the next structure that you see here, once we have reflected it very carefully, this is the very fragile cadaver, muscles are very atrophy, but we have managed to take out the layers. This is the next layer. What is this layer? This is the internal oblique. If you notice, the fibers are taking origin from the lateral one half of the inguinal ligament, which I showed just now. It is taking origin from the middle lip of the iliac crest and the fibers are going up like this and they will get inserted onto the 10th of the 12th ribs and they will also form part of the rectus sheath as well as the linear alba. So this is the internal oblique. Now let me reflect this very carefully. Now we see the third muscle. This is the transversus abdominis and you can see the fibers are running transversely. They are also taking origin from the lateral one fourth of the inguinal ligament. To remind you, this was the inguinal ligament. And you can see these curving fibers here. These are the lower fibers of the internal oblique and transversus abdominis, which form what is known as the conjoined tendon or the fax inguinalis. So therefore, this is the region of the inguinal canal and this is the female cadaver. So therefore, the canal canal is not prominent. We have highly exaggerated, but I'll come back to it later. The fibers also take origin from the innermost lip of the iliac breast and they also take origin from the thoracolumbar fascia, which is behind. The fibers go transversely. They get inserted onto the 7th of the 12th ribs and this transversus abdominis aponeurosis. It forms the posterior layer of the rectus sheath, which you can see here, but I will show it to you more clearly just a little while later. So if you remember the layer between the internal oblique and the transversus abdominis is the neurovascular plane. Therefore, we can see one nerve here. So nerve fibers are the thoracoabdominal nerves. They will come from the thorax and they will go like this and they will go and supply. So this was the plane in which they run and they not only supply these muscles, they also supply the rectus abdominis, which I'm going to show you just now. So let me bring these muscles back. So transversus abdominis, internal oblique and external oblique. Now we all know that the anterior layer of the rectus sheath is formed by the fused fibers of the anterior leaf of the internal oblique and the external oblique. So this is the external oblique. Now this particular cadaver, as I told you earlier, had an undergone a surgery and you can see this used in material. So therefore this portion was highly fibrosed. So we had to do some tough dissection, but we have managed to separate out the anterior layer of rectus sheath. So this is the anterior layer of rectus sheath. My assistant has lifted it up and you can see the muscle underneath. I'm lifting out the other segment of this and you can see the muscle underneath. This is the right side rectus abdominis muscle and you can see this white fibers here. This is one of the tenderness intersections. So we have cut out the rectus abdominis muscle from its attachment to the fifth to the seventh costal cartilage here. So therefore this is the insertion of rectus and the origin of the rectus is here. If you feel carefully it is attached, originating from the pubic crest at the symphysis pubis. So this is the rectus abdominis muscle. Now this is another tenderness intersection. This was a tenderness intersection above. Now what we are going to do is we are going to reflect the rectus sheath and the rectus abdominis muscle. That is what we have done now. So just to bring up the speed, gentlemen and ladies, we are looking at the posterior aspect of the rectus abdominis muscle. I hope everybody has understood. So we can see in the posterior aspect. So this layer that we see here, this is the posterior layer of rectus sheath. We have separated it out and this is the posterior surface of the rectus abdominis muscle. I hope it's clear to everybody. So what do we see here? We see a neurovascular bundle running here from below up and my assistant is going to hold it here. What do you think this is? This is the inferior epigastric artery and vein. Where does this inferior epigastric artery come from? It comes from the external iliac artery. And how does it enter into the posterior layer of rectus sheath? It runs through this arching portion here. This is the archivate line. So you can see, if I lift it up, you can see that this is slightly translucent here because this is where there is no posterior layer of rectus sheath. So it enters in the posterior layer of rectus sheath. Now, let me come back to the inguinal canal. Well, my assistant is still holding this neurovascular structure. In the inguinal canal, the so-called inguinal canal because it's a female cadaver, these are the conjoined fibers, conjoined tendon fibers. If I retract them forcibly, we can see two structures. We can see this here. This is the inguinal nerve. The inguinal nerve is L1. It will go and supply the upper medial thigh and will supply the labia mesura or scrotum. Let's push that aside. The next structure that we see here is this one here, which I have lifted up. This is the inferior epigastric artery. If this had been a male cadaver, there would have been a deep internal ring just lateral to that. So this is the landmark. Now, how do we prove it? My assistant is going to pull on the inferior epigastric artery behind the rectus abdominis. And when she pulls, can you see this moving here? Relax. Pull again. Relax. Pull again. So that proves that this is the inferior epigastric artery. This inferior epigastric artery is a very useful landmark when we're doing an indirect inguinal hernia. The indirect inguinal hernia, it arises from the lateral inguinal fossa, lateral to the inferior epigastric artery, while a direct inguinal hernia arises from medial to the inferior epigastric artery, which is the haselback triangle or the medial inguinal fossa. So these are the structures which I wanted to show you, ladies and gentlemen, in the dissection of the anterior abdominal wall and its muscles, its fascia, its sheath, and the related structures. Thank you very much for watching. Dr. Sanjay Sanyal, Sanyal, 21 students are my assistant. Have a nice day. Please like and subscribe.