 Welcome to our next dissection. I'm Dr. Sanjay Sanyal, Department Chair of Nativical Sciences. And today we are going to demonstrate the structures on the back of the thigh, continuing into the perp-retail fossa and a little bit into the upper part of the back of the leg. So let's bring you up to speed. This is the continuation of one of the previous dissections. The muscles that you can see straight away in front of you. This is the hamstring group of muscles. As you can see, they're taking origin from the eschewed tuberosity here. The most important muscle in these groups, you can see this model here. This is the bicep femoris. The bicep femoris has got a long head which takes origin from the eschewed tuberosity. And if you look deeper inside, you'll see a short head which takes origin from the back of the femur. So this is not a true hamstring, but this is part of the biceps. This is a different perspective of the biceps using a different camera from the opposite side. The reason I showed you this clip is to show you the short head arising from the posterior aspect of the femur, which I said is not the true part of the hamstrings, but it's included in the biceps. Okay. Other groups of the hamstrings, this is the lateral group of muscles in the, the medial group of muscles in the posterior compartment of the thigh are these two muscles that we see which I've lifted up here. This is the semi-tendinosis. And you can see that the distal part of the tendon is more tendinous in structure. That's why it's called semi-tendinosis. And the one just deep to that. This is the more fleshy one. This is the semi-membrinosis. Just to bring you up to speed, the semi-tendinosis gets inserted in the region of the tibia, which is referred to as the pest and serenus, which takes the combined insertions of the sartorius, gracilis and semi-tendinosis. The semi-membrinosis on the other hand is inserted onto the upper part of the medial surface of the tibia and it gives plenty of expansions to the posterior capsule of the knee joint. Okay. Having said that, I need to, the story will not be complete unless I mention the other part of the muscle of the, which is not strictly a muscle of the hamstring group, but it is a function and that is this muscle that you see here. This is the adductor magnus. Adductor magnus, most of it is the adductor group, but we can see that it has got a component which is taking attachment from the pronationative velocity and that component is referred to as the hamstring component and that is shown here. I've introduced this clip to show you the adductor magnus from the opposite side. The fleshy part of this muscle, which you can see between my fingers, most of it is the adductor component taking origin from the liniasper and the back of the femur. However, there's a portion which is tenderness and under my left hand, if you see closely on this side, that is the hamstring component taking origin from the ischial tuberosity. Now, let's take a look at the important content and the most important content of the back of the thigh, which runs behind the hamstring is this nerve here and you can see this is the sciatic nerve. I had already mentioned this when I was talking about the gluteal region and we can see that it is coming out from the gluteal region. It is coming between the ischial tuberosity and the greater trochanter. It's running in this groove here and now it's come to the back of the thigh and we'll trace the sciatic nerve all the way down here. This is the sciatic nerve which is running deep to the hamstring muscles. These are all supplied by the TBL division of sciatic nerve and they are running wide. I've inserted this clip of the sciatic nerve from yet a third perspective to show you the course of the sciatic nerve from the gluteal region to the back of the thigh. As you can see, it runs between the ischial tuberosity and the greater trochanter and it is here it can rub against the ischial tuberosity to produce the condition known as sciatica, a painful condition. On this place, I can show you that this is the hamstring component. This is the hamstring component of the adductor magnus and we can see the perforators. Some of the perforators we can see. Remember the profunda femoris give rise to multiple perforators and some of these perforators you can see they are all perforating through coming out from the adductor magnus. Let's continue. In the lower part of the thigh back of the thigh you can see the sciatic nerve is divided into a lateral branch and a medial branch. This is the tibial nerve. Some books call it the medial-puppetial nerve but we don't with the tibial and the lateral branch is the common fibular. The common fibular runs under cover of the biceps femoris. We shall see when we come to the leg it winds around behind the head of the fibular and then goes around the neck of the fibular and it supplies the antirelateral compartment of the leg which we shall see later on. As it winds around behind the head and around the neck of the fibular this is the place where it is very liable to injury either from fracture of the neck of the fibular or otherwise. Then it produces paralysis of the muscles of the antirelateral compartment of the leg and produces the severe condition called foot drop. Let's take a look at the tibial nerve. Now we are in the region of the propritial fossa and you can see that the propritial fossa before I tell you about the tibial nerve let me tell you quickly about the boundaries of the propritial fossa. Let me put the muscles back in the normal place. Can we see that the medial boundary is formed by the semi-tendinosis and the semi-membrinosis? The lateral boundary is formed by the biceps. So supramedial supralateral it's a diamond shaped. The intromedial boundary is formed by the medial head of the gastrocnemius and you can see here this is the medial head of the gastrocnemius. Gastrocnemius is the muscle of the calf which gives you the rounded appearance of the calf and this introlateral boundary is formed by this muscle which is also part of the gastrocnemius, the lateral head of the gastrocnemius. So this diamond shaped cavity is the propritial fossa. This was bridged over by the propritial fascia, a tough fascia which has been removed. Now let's continue with the contents of the propritial fascia. Straight away we can see that the continuation of the tibial nerve is coming here. It is running from one apex of the propritial fossa and exiting through the other apex of the propritial fossa. So this is this most important central component. Now you can see clearly the diamond shape of the propritial fossa which in life was covered by a tough fascia called the propritial fascia and now that it has been removed you can clearly see the tibial nerve is running, entering it from one apex, it is going through the length of the propritial fossa and then it exits out through the other apex. So this is the clearly visible propritial fossa. The most important central component of the propritial fossa. The next structure that we see in the propritial fossa is this. This is the propritial vein and the propritial vein is the next in depth after the tibial nerve. And finally the grand idea of all structures is this which is the propritial artery. Now if you remember we had mentioned that the propritial artery and the propritial vein they enter the propritial region by passing through a hiatus here and that is the hiatus you can see here. My finger has gone into the hiatus. This is the adductor hiatus and this adductor hiatus is an opening in the adductor magnus tendon from where this propritial artery and the propritial vein above this they were called the femoral artery and femoral vein. When they came out through the adductor hiatus into the propritial region now they are called propritial artery and propritial vein. And we can see that the disposition of these structures are from lateral to medial is the nerve vein artery and from superficial to deep is also the nerve vein and artery. In other words the carry home message is that the propritial artery is the deepest structure in the propritial fossa and it's the medial most structure. And both of them they supply all the stuff. Just now we saw in the class today that the propritial artery gives rise to five genicular branches which supply and some of those branches were there but I have removed them. I've introduced this clip to show you three things. One I wanted to show you the adductor hiatus again in more detail and you can see my little finger is going into the adductor hiatus from where the propritial vessel femoral vessels continue into the propritial region and they come to be known as propritial vessels. And you can see this propritial hiatus in the adductor magnus in the well-recognized site of entrapment of the propritial artery. That's the first point I wanted to mention. The second point I want to emphasize was as a propritial artery is running in the propritial fossa being the deepest structure it is level two entrapment by the medial head of the gastropanias what is known as propritial artery entrapment syndrome, P-A-E-S. Now that's a very complicated classification involving six levels of classification but we will just keep it simple by saying that it gets entrapped by the medial head of the gastropanias. And finally, when the propritial artery exits the propritial fossa it can get entrapped under the solial arch as it goes into and divides into artery and posterior tbl arteries. These are the contents and before I conclude I need to show you something else. This what you see here is the floor of the propritial fossa. So the upper part of the floor is formed by the posterior surface or the intercondyler surface of the femur. The middle part of the floor is formed by the posterior surface, posterior capsule of the knee joint and the lower part of the floor is formed by this muscle that you can see here this is the fascia covering the propritius muscle. This is the propritius muscle which runs from medial to lateral obliquely up and which we shall see but we did mention it in the class today and this is the muscle which is actually knee muscle of the leg. So these are the structures which I wanted to show you and thank you very much for watching ladies and gentlemen if you have any questions or comments have a nice day. Thank you camera person.