 Dr. Sanjay Sanyal, Professor Department Chair. This is going to be a demonstration of certain surgical aspects of the fascia letter, superficial veins and the superficial nerves. More specifically, this is going to be a rather unique demonstration about the anatomical basis of certain aspects of surgical physiology. This is supine cadaver. I'm standing on the left side. Camera person is on the left side. So let's take a look at this fascia which we have lifted up here. We have slid it here and this is the fascia that we have lifted up. And you can see it clearly on the medial side and I'll do the same thing on the lateral side. We can see this fascia here. This is the fascia letter of the thigh. The fascia letter of the thigh is a very thick deep fascia which completely invists the thigh, like a cylinder. Superially, it is attached to the inguinal ligament. You can see that here. And inferiorly, it continues and it becomes continuous with the fascia of the leg and the fascia of the knee. It completely forms a cylindrical encircling of all the muscles and the deep muscles of the thigh. On the lateral side, it gives a septum, a very prominent septum called the lateral intermuscular septum, which covers the vascular lateralis and it gets attached to the posterior aspect. That is the linear aspera. The medial part has got two intermuscular septum but they are not very prominent. This fascia letter of the thigh, laterally as it continues, it becomes extremely thick. And we can see that here and I have retracted the lateral part and you can see how thick it is. So we can see that this is the interior of the lateral aspect of the fascia letter and this is so thick that it's almost like a cartilage. This is called the iliotibial tract. This has got a completely different function. This provides an aponeurotic expansion of two muscles. One is the gluteus maximus and the other is the tensor fascia letter. Both of them are gluteal muscles and it gets attached to a tubercle on the antrilateral aspect of the tibia called the tubercle of the journey. Having mentioned that, now let's come back to the fascia letter itself. This acts like a compartment. Take for example a patient who has sustained burn of the thigh. He gets fluid exudation under the fascia letter and that is called a third space loss. Inside the blood vessels, inside the cells, third space means outside of these two structures that's what's called a third space loss. Similarly, if a person gets a fracture of the femur, the person can get a loss of blood into the third space as much as 2.5 to 3 liters. Now this third space loss can lead to hyperbolic shock in the patient. So therefore it is important while calculating the fluid replacement to calculate the volume of fluid loss. And for that, what we do is we measure the circumference of the normal thigh and then we measure the circumference of the swollen thigh and use the formula of a cylinder by our squared edge and we determine how much is the excess volume and that determines how much is the third space fluid loss which will help us in calculating the fluid balance. So that is one aspect of this deep fascia or the fascia letter of the thigh. The next point which I want to emphasize is if you take a look at the inguinal region where I said the fascia letter is attached, if you look just superficial to the inguinal ligament you will find this structure which I have lifted up here. This is the membranous layer of the abdominal fascia, the superficial fascia of the abdomen and we can see that clearly here. The membranous layer is known as the scar pass fascia. The scar pass fascia comes down from the abdomen and it gets attached to the upper part of the fascia letter just below the inguinal ligament and this line of attachment is called the Holden's line. Have you ever wondered when we are doing an abdominal examination of a patient, we ask the patient to slightly flex the hip? The reason for that is when we ask the patient to flex the hip, we make this fascia slightly lax and therefore it enables us to palpate the abdominal contents. So that is the surgical basis of this attachment of the scar pass fascia to the fascia letter. Now let's take a look at some other aspects. We can see these superficial veins. These are the tributaries, this is the long syphilis vein and these are the tributaries and we can see that they're piercing through this opening here. This is called the syphilis opening and we can see it's got a sharp lateral margin and a blurred medial margin and after piercing through the syphilis opening, it opens into the femoral vein and we can see many other tributaries here. All these tributaries as a matter of fact, they pierce through the fascia letter. So for that I'm going to reflect this medial portion of the fascia letter and when I reflect we can see the structure. This is actually, and if we zoom the camera closely, we can see that here there's a vein here in the middle and there's a nerve here. These two structures, they pierce through the fascia letter and they go out and they come superficially. So we know that through the opening in the fascia letter, the vein pierces and this cutaneous nerve also pierces and the cutaneous nerve then supplies the skin and the vein. This vein which pierces through is referred to as the perforating vein and the perforator. The perforators communicate with the superficial veins and the blood normally flows from superficial to deep and they are directed by unidirectional valves. If these perforating veins become incompetent, then blood will flow in the reverse direction from deep to superficial and will lead to localized variceal dilatations of the superficial veins which they happen when they happen on the middle side of the thigh, they refer to as the philampharex. So this is one such structure which I showed you. Let me show you yet another one on this side. We can see here, there's an opening which we have enlarged and we can see this vein coming out and accompanying that is the superficial cutaneous nerve and we can see that nerve also here. So this is one of the branches of the anterior femoral cutaneous nerve which is the branch of the femoral nerve and we can see this vein also. And if I turn this back, we can see this is the vein and this is the nerve. So both the vein, the perforating vein and the cutaneous nerve, they go through these openings. Now we shall come to the lateral aspect and we can see some more of these things in a much more prominent vein. We can see this vein penetrating through. This is a perforating vein. We can see another vein penetrating through. This is another perforating vein. I'm going to lift up the lateral aspect and we can see if I turn this, to zoom the camera, we can see that this is the place where it is perforating through. The reason why they're called perforating veins is because they perforate through the deep fascia and they transmit blood from superficial to deep. And as I mentioned, the blood is always unidirectional. If these valves become incompetent, then the reversal flow occurs and it leads to localized allitations. When these things happen in the leg, then it leads to varicose veins. And in the leg, there's a surgery where they do subficial ligation of these perforating veins which is a rather tedious surgical procedure. Let me come back to this opening which I had mentioned earlier. This is called the saphenous opening. This is an over-shaped opening in the upper part of the fascia letter through which several structures pierce through. This was covered by a thin membrane called the cribriniform fascia which we have removed. It is pierced by, we can see the long saphenous vein which I mentioned opens into the femoral vein. It is also pierced by the lymphatics which drain lymphatics from the superficial to the deep group. Superficialing 1L to the deeping 1L lymph nodes. So because they are perforated by multiple lymphatic channels, the thin membrane is called the cribriniform fascia. The word cribriniform means multiple sieve-like openings. I will draw your attention to these nerves which I had mentioned earlier. These are the branches of femoral nerve. And there are hundreds of them which we have picked up, only two of them. These are known as anterior femoral cutaneous nerve. They supply a large portion of the anterior and the medial portion of the thigh. Then I will draw your attention to these nerves which we see on the lateral aspect. This is the lateral femoral cutaneous nerve. This is a separate nerve all by itself which comes from the posterior division of the lumbosacral plexus L23. It goes under the inguinal ligament and it pierces through the deep fascia and it supplies the skin on the lateral-lateral aspect. If this nerve gets entrapped under the inguinal ligament on the lateral aspect where it is attached to the anterior superior iliac spine here, then it can lead to tingling, numbness and parasthesia in this distribution. That is referred to as Meralgia Parasthetica. Finally I will draw your attention to this nerve. If I turn this in inguinal ligament, we can see other portion of this nerve here inside the inguinal canal. This is the ilio-inguinal nerve. The ilio-inguinal nerve runs in the inguinal canal and one branch of it goes and supplies the intramedial aspect of the thigh. The other portion of course supplies the skin of the scrotum of the labia majora. The branch which supplies the thigh, that serves as the effered limb of what is known as the trimester reflex in young male children. So that is another nerve that we can see here. So what we have seen essentially in this dissection are the facial atta, the thickened lateral portion called the iliotibia tract. We have seen the perforating veins. We have seen the superficial veins. We have seen the cripple-formed fascia, the subvenous opening. We have seen the cutaneous nerves. We have seen the scar-pass fascia attached to the fascia atta just below the inguinal ligament. And we have seen the surgical significance of this fascia atta and the perforating veins. That's all for now. Dr. Sanjay Sanyal signing out. Mr. Ken Lohan Khambur Batch is the camera person. Thank you very much for watching. If you have any questions or comments, please put them in the comment section below. Have a nice day.