 So, this is a demonstration, a detailed demonstration of the structures which are located in the entire anterior abdominal wall. This structure which I have picked up here, this is the membranous layer of the superficial layer of the abdominal fascia that is known as the scarpa's layer. And on top of that we can see a little bit of fatty streaks that is the remnant of the campers or the fatty layer of the superficial fascia. This completely invests the anterior abdominal wall and it continues down, I am talking of the scarpa's layer and it gets attached to the fascia later of the thigh here and it also becomes continuous with the colis fascia of the perineum. In the midline we have this crisscrossing fibres here, this is the linea alba. This linea alba is a very tough structure and we can see closely here that the fibres are crisscrossing here and here also. The linea alba is formed by crisscrossing fibres of the rectus sheath from the right side and that with the left side. The word linea means straight and alba means white so it is a white straight line. This is the umbilicus which is a weakness of the linea alba from where the umbilical cord emerged. The linea alba is a very tough fibrous psychiatric caused by the intermingling fibres from the right side and from the left side and they also contain fibres crisscrossing from one external oblique aponeurosis to the opposite external oblique and it also contains fibres crisscrossing from the external oblique of one side to the internal oblique of the other side. Now let's take a look at the what is the rectus sheath. The rectus sheath is a tough layer of fascia both anteriorly and posteriorly which are running in the anterior abdominal wall and it gives strength to the intra-abdominal wall by virtue of a muscle inside it. The anterior layer of the rectus sheath which we have split open and reflected. This is one leaf and this is the other leaf of the right rectus sheath. The anterior layer of the rectus sheath is found by the aponeurosis of the external oblique muscle and by the anterior leaf of the aponeurosis of the internal oblique muscle. So these two together fuse as we can clearly see here they fuse and they form the anterior layer of the rectus sheath. The posterior layer of the rectus sheath is formed and the posterior of the rectus sheath is here is formed by the posterior leaf of the aponeurosis of the internal oblique and the aponeurosis of the transversus abdominis which I showed just now. This is the aponeurosis of the transversus abdominis. So this layer and the posterior aponeurosis of the internal oblique forms the posterior layer of the rectus sheath. So this is how the rectus sheath is formed. This is the situation which is there in the upper 3 fourths of the rectus sheath. The lower 1 fourth of the rectus sheath all the 3 aponeurosis external oblique internal oblique and transversus abdominis they all come in front of the rectus abdominis and behind the rectus abdominis we have only the fascia transversalis and I will show you the junction and that junction is referred to as the arcuate line. The lateral margin of the rectus sheath is this one and this slightly curved line is referred to as the linear seminunaris which marks the lateral limit of the rectus abdominis muscle. This extends from the body of the pubis and it ends at the 9th costum cartilage. Now we shall reflect the anterior layer of the rectus sheath to show the muscle underneath. This is the very powerful and strong muscle and this is called the rectus abdominis. So we have the rectus abdominis on this side. This is the other leaf of the rectus sheath on the right side. Now we have also reflected the rectus sheath on the left side. This is one leaf of the rectus sheath and this is the other leaf of the rectus sheath and to show the rectus abdominis muscle on both the sides. So this is the left rectus abdominis muscle, this is the right rectus. The word rectus means straight and this is the one which gives the bulk of the strength to the abdomen and this is the muscle which the boxer strain to strengthen because it gives a lot of support to the internal organs. It takes origin from the anterior surface of the 5th, 6th and 7th ribs and it gets inserted onto the body of the pubis. At the place of origin from the anterior surface of the ribs there is no posterior rectus sheath. This muscle has got tendinous intersections and we can see 1, 2, there will be 3 tendinous intersections and there may be a 4th one and we can see the similar tendinous intersections on the other side also 1, 2, 3 and there may be a 4th one and these tendinous intersections are the ones which break up the muscle into 4 segments and they are also attached to the rectus sheath anterior layer of rectus sheath which we have separated. The action of the rectus abdominis muscle is to flex the lumbar spine and it also is an anti-lordotic muscle so that is under of course it of course affords tremendous protection to the abdominal contents. The supply of the rectus abdominis muscle is also the same thoracobdominal nerves which I described and because of its segmental supply even in surgical practice we can safely cut the rectus abdominis muscle without jeopardizing its nerve supply because the nerve supplies are segmental. So here we have cut the right rectus muscle just to lift it up to show you what is underneath so we have reflected up the upper half and the lower half to show you some important structures. So this is the posterior of the rectus sheath here. We can see running from below is a very important artery and accompanying vein and this is the inferior epigastric artery and we can see that this artery is arising from the external iliac artery. The external iliac artery passes under the inguinal ligament and then it becomes known as the femoral artery. So this much is the external iliac artery and this is the inferior epigastric artery and when I exert traction here we can see that this is moving. So this is the inferior epigastric artery and this is the accompanying inferior epigastric vein under that which is arising from the external iliac vein. How does the inferior epigastric artery enter the posterior layer of the rectus sheath? I mentioned to you a little while back that the posterior rectus sheath which is visible here in the upper three fourths it has got a different construction and the lower one fourth has got a different construction. The upper three fourths is formed as I told you by the posterior leaf of the internal oblique and the aponeurosis of the transverse abdominis but the lower one fourth that is from here to here all the layers of the aponeurosis come anteriorly and therefore posteriorly there is no aponeurosis only fascia transversalis and we can see that there is no aponeurosis there is only fascia transversalis and on the underside of that inner side of that will be the preperitoneal fat and the peritoneum. So the junction between the upper three fourths and the lower one fourth is this curved line here and we can see the curved line very clearly here. We can see this line here this curved line is referred to as the arcuate line. This arcuate line affords the location where the inferior epigastric vessels enter into the rectus sheath. So this is the reason why the lower one fourth of the posterior rectus sheath is deficient. This inferior epigastric vessels they are running between the posterior layer of the rectus sheath and the posterior surface of the rectus accumbus muscle and they anastomous with this artery which is coming from the top and this is the superior epigastric artery which is one of the terminal branches of the internal thoracic artery and this comes from above and both of them anastomous and this is the blood supply of a major blood supply of the anterior terminal wall. Incidentally the accompanying vein to this artery and the accompanying to this artery they also form a site of anastomosis between the inferior vena keva and superior vena keva because the superior epigastric vein drains ultimately into the superior vena keva inferior epigastric vein drains ultimately into the inferior vena keva. So therefore, this is site of anastomosis in superior vena keva and inferior vena keva and incidentally once we have reflected the rectus abdominis we can see its unique segmental nerve supply by means of the thoracoabdominal nerves we can see one nerve here we can see another nerve here a third nerve here a fourth nerve here and a fifth nerve here we can see the unique segmental nerve supply. So therefore as we do in surgery if we cut it here both the segments their nerve supply is intact and therefore we do not jeopardize the nerve supply of the muscle that is what I wanted to show you about the rectus muscle and the rectus sheen. So that is all for now thank you very much for watching if you have any questions or comments please put them in the comment section below Dr. Sanjay Sanyal signing out have a nice day.