all right it is too warm in my office wait never complain about the weather in Wales when it's warm if it's warm and sunny it's a rarity where is their lab the anatomy lab is nice and cool guess why we like to have a nice cool Anatomy labs yeah there's there are some good reasons why you don't let your Anatomy labs get too warm it's not a good thing so last week we were talking about the veins of the upper limb and I had a few requests and it's look see that it's supposed to be on it seems incredibly logical that we should then do the veins of the lower limb and I also had a couple of requests so today we're going to do the veins of the lower limb and there are actually some veins on these models of the lower limb so that's a good start [Music] okay so how are we gonna do this we are going to do the same sort of thing with it last time there are a bunch of important superficial veins in the lower limb we'll do the superficial veins well I have pipe cleaners for again so we'll have to make those then we'll do the deep veins and in the lower limb the association between the superficial veins and the deep veins is a little bit important well have a look at the deep veins will follow them will do the superficial veins from like this stool from the foot up to the the hip and then we'll do the same for the deep veins will link those together and then we need to talk about things like the muscular venous pump but also we should talk about varicose veins why do we get varicose veins which veins become varicose and DVTs deep vein thrombosis so the veins in your legs can kill you what so how does a blood clot a deep vein thrombosis in the lower limb how does it kill people why is it so dangerous we'll have a look now do you remember in the upper limb see like when you've got all the latches down it doesn't fall apart do you remember in the upper limb there was a dorsal venous plexus of veins on the back of your hand well there's also the dorsal venous plexus of veins on the dorsal surface of the foot this is the dorsal foot this is the plantar foot you stand on the plantar foot and those veins come together and they form a very long vein which runs from here superficially all the way up to the thigh up here and that's the gratefulness vein or the long saphenous vein if there's a long one that's going to be a short one there's great mums gonna be a smaller so it it's these this plexus of veins here in the foot that are coming together and forming these other veins now as in the upper limb and as with veins elsewhere in the body body one we talk about an artery following this path and most people's arteries will follow similar paths and be arranged similarly the arrangement of veins is much more variable if you look at the veins in you in your forearm and the veins in your leg you see a lot of subcutaneous veins and they all look a little bit different in each other so that we have a couple of major veins that follow a typical route that you should be able to find in everyone or most people but then there will also be other veins like a random almost plexus of veins cutaneous veins under the skin they're also draining blood from the superficial parts of the leg so we're going to talk about the the main veins that we can follow right quite clean the time all right let's put the elastic bands on they're gonna hold things in place I'm gonna make a really long chain of pipe cleaners to make this thing it should be fine go too far we go to here okay so the long saphenous vein or the great saphenous vein you should be able to find if you look here so these area of the body has very little subcutaneous fat and this here this is the tibia so this is the medial malleolus of the tibia right there's the big toe so on the medial side now just anterior to the medial malleolus of the tibia that's where you should find the start of the great saphenous vein shortly just I'm not going to be a very good to him of the great saphenous vein on myself today have a look on yourself right find your great saphenous vein but it's here so it runs so it collects that blood from the foot all right got the dorsal venous network we've also got a dorsal vein of the great toe that contributes to it that's over to this side and then to see so it stays superficial it runs from anterior to the medial malleolus and it's running to the medial knee it's gonna go around to this point here somewhere and then and then it's gonna kind of keep running up the medial thigh but it's trying to get to this spot here so do I just need like a short one there alright a bit too long yeah there we go so there are things like that so what we've got here is the femoral vein and the femoral vein is going to pass underneath the inguinal ligament here and become the external iliac vein but more importantly than that is do you remember when we were talking about the upper limb we said that essentially these models are showing deeper structures the reason they don't show the superficial veins is because we've detected away the skin so we've defect the sectored away the cutaneous veins the superficial veins and we've detected the way the fashio over the top the connective tissue covering this holding all this in place now the lower limb is covered in like a stocking fashion of deep fascia and we see a bit of here this is the iliotibial tract this is a thickening of that fashion but the fashion gets called the fasciae latae and it's covering imagine a stocking covering this entire lower limb is holding everything not it so it's deep to the veins right deep sorry you know it's it deep to these superficial veins but it's it's it's holding everything in place that's what Sasha does but there's a hole here and it is the saphenous opening and this little hole so imagine a hole in the stocking there allows this long saphenous vein to drain into the femoral vein here so this superficial vein is eventually draining to a deep vein which goes into the pelvis and the abdomen and up so that's the great saphenous vein another important consideration when we're thinking about the veins of the lower limb is that we need to return blood from our feet back up to the heart how are we gonna do that as a heart gonna suck the blood up I mean you imagine having a straw that long and trying to suck the fluid up from doable but that's that's some negative pressure you've got a generate also of course you're you're pushing blood down the arteries are higher pressure through the capillaries and then pushing the blood back up again so you kind of got both things working in action but the lower limbs because we are standing up we've got quite long lower limbs the heart needs a little bit of help one of the ways of helping the heart return blood from the foot from the lower limb to the abdomen is by the use of valves so there are maybe what dozen valves I think in there in the great saphenous vein and blood you get pushed up the vein and the valve opens and then as the the blood settles back down again the valve closes and bubble bubble-butt yeah so that we don't have this the full height of column of blood we actually have most smaller shorter columns because we have these columns between the so it makes it easier to return the blood from the foot all the way up the lower limb and back up into the pelvis by the use of valves that's when the valves work properly all right so that's the great saphenous vein I know back in the day the great saphenous vein used to be a target for heart surgeons who have a cardiac surgeon so if you wanted to do a coronary bypass so if somebody's coronary artery had become occluded you would take out a section of the long saphenous vein because it's superficial it's easy to get to either avoid the valves or flop it around the other way and then you could use that vein and stitch it into the the take out the coronary artery at those blocks and stitch in a new blood vessel right into that coronary arteries you could do a heart bypass in that way totally still do that or if it if they by you know if it's all them manufactured tube these days don't know I'll ask my friendly neighborhood cardiac surgeon right that's the great saphenous vein no the short saphenous vein runs up here so the short saphenous vein kind of comes over from this side but it's running up here and this is gastro knee meais gastrocnemius and soleus so this is a vein that's very superficial oh it's almost long enough if I pull up it's kind of long enough there we go it's a superficial vein under the skin this is a vein you may well see in some very very skinny people and it's collecting blood so there is a dorsal vein of the little toe and you've got that dorsal venous network all those blood vessels are coming together I wonder if the plantar veins also contribute to it probably and this is the the short saphenous vein or the small saphenous vein so this runs underneath the skin in the calf and ends here so it's draining into this is the popliteal fossa in the posterior knee so that's where it passes from superficial to deep to drain into the popliteal vein and we'll look at those deep veins in a moment and then the blood carries a back up to the pelvis now again this vein has valves and it's this vein you may encounter varicose veins in so with veins don't have a nice muscular wall to them like arteries do I'm not really used to handling high pressures with his veins handle low pressures but if you've got a column of blood running down here and the weight of that blood is on the valve and I said we've got shorter columns but still if the vein starts to distend if it starts to stretch then the valve starts to become incompetent it doesn't work very well because it's getting pulled apart which then puts more pressure on the valve underneath it and underneath it and underneath and so on and then the veins have more weight on and they start to stretch more and then we start to see those Wiggly veins often in the posterior leg in the calf here and those are varicose veins so the the veins have started to stretch the valves have started to break down and it's you know it's kind of progressive so it's the short saphenous vein you may see that only might we might see elsewhere on the lower limb as well but so these are the two big superficial veins of the lower limb but I imagine other cutaneous veins underneath the skin if you look at your own lower limbs you'll probably see them so imagine all of those veins draining into into these veins and what have you now I talked about the great saphenous vein coming up here and then passing through the fasciae latae to drain into the femoral vein here but in fact as the vein ascends there are a number of connections between the superficial veins and the deep veins and those perforating veins because they're perforating through the fascia also have valves so there is a one-way flow of blood from superficial to deep veins through those perforating veins so in fact I think the saphenous vein as it ascends and it receives more tributaries more cutaneous veins draining into it it doesn't get noticeably larger and if you think about a river as it gets more tributaries that River gets bigger and bigger and bigger because it has to handle more water more flow whereas we don't see the same thing in the great saphenous vein because those perforating veins are constantly sending some blood from the the long saphenous vein to the deep veins so perforating things and that relates to the musk you know venous pump which I'll come back to in a minute but first of all let's have a look at the deep veins then so elastic band fail the deep veins run with the arteries I've done a video on the arteries of the lower limb to go and have a look at that again this means that you don't need to learn the arteries and the veins of the lower limb separately if you learn the arteries of the lower limb then the deep veins match that layout alright we have tried the superficial veins on top the deep veins run with the arteries kind of in a vascular sheath so they're close to the arteries supposedly the pulsation of the artery the pressure in the artery helps squeeze blood up the veins back to the pelvis so they say but just like in the upper limb we find that the deep veins often run in pairs all the time but often if we see a single artery in the lower limb we'll see two veins running with it often interconnecting as they go so there are some things on him let's take this apart and see what veins we've got right now okay there's no vein there this is the the anterior tibial artery so there I didn't think I'd have to didn't think I'd have to build again a fort of veins would be on it let's build again so the if I got a short one shortish one so the dorsal venous network him and the dorsal venous network of veins I'm also going to contribute to form so if that's the anterior tibial artery like a most likely there will be a pair of anterior tibial veins I'm not doing a brilliant job of that but you see how it was so it's this is in the anterior compartment of the leg the leg being between the knee and the ankle so if we take off the muscle layer then we see the anterior tibial artery so the two anterior tibial veins will be in there as as as theirs as well and not long enough but just see how the anterior tibial artery is disappearing there you've got two bones we've got the the the the fibula is lateral and the tibia is is medial a/c ashamed right between the two bones there's a connective tissue sheet a membrane and interosseous membrane that connects the bones and separates the compartments anterior and posterior so this means that the anterior tibial artery and the two anterior tibial veins are going to have to pass through the interosseous membrane and they do that up here to get into the posterior compartment because if we look at the posterior compartment again we're talking about deep veins so let's dissect under the way there's take gastrocnemius and soleus off so here we see the posterior tibial artery oh there's a vein starting up there so the posterior tibial artery would have probably - posterior tibial veins were running no with it deep within in the leg and these are coming these are forming most likely from plantar veins medial and lateral plantar veins on the plantar surface of the foot on the underside just as we see the arteries he doing now when the so there's also another compartment in the leg we have the lateral compartment out here so from the lateral compartment there will also be a pair of fibula veins I can't take these muscles off so maybe use your imagination rather than me confuse you but so we can make it we can pretend right so like there's there's the fibula there these are the fibula muscles so imagine although there's the fibula veins are appearing from over there there they are they're coming out of that lateral compartment and they're all converging here so we have the fibula veins the posterior tibial veins and those anterior tibial veins are going through the interosseous membrane they're all converging here so all of those deep veins of the calf are converging in this bit here so this bit in the posterior knee this is the popliteal fossa so these veins all come together to form and we've got that here this is the the popliteal vein here the model only shows one vein but they will probably be a couple of popliteal veins so we need to set in this area it can be terribly confusing you've got nerves all over the place you've got an artery that's making all sorts of funky branches and you've got a whole bunch of other vessels if you've got too many vessels those are probably a pair of property or veins coming together so that's that and can you see how we've got some little arteries around here so remember that whenever we look at the blood supply through a limb as we cross a joint we find collateral circulation so we have Janicki --let veins and Jen you literally meaning the Sojin Aquila vanes are matching these janila arteries around the knees we got these little Janicki levain branches around the knee here as well which also crossing the knee joint you can get various anastomosis if we follow the popliteal vein it's nice so this is the this is the Sartorius muscle here we take off the Sartorius muscle underneath the Sartorius muscle we have this sub sartorial canal and you see how it's going from the lateral to the medial so it's running to the medial knee here and look we can see some veins under here this is the femoral vein so the popliteal vein is going to become the femoral vein so it's going to this is the medial compartment your abductors in here and adductor Magnus to the really big adductor muscle is gonna have a little gap in there the adductor hiatus so the popliteal vein will pass through the adductor hiatus none of this comes off and it will become the femoral vein which will run up here into the anterior compartment of the thigh all right the femoral vein as we said before runs up here and then as it passes underneath the inguinal ligament becomes the external iliac vein there is also a profunda femoris vein so a deep vein of the thigh which is actually going to be draining most of the blood from these muscles that's going to be deep under what do we do we have that nope you can see if some very are various arterial branches for imagine some veins running with those guys but there would be a profunda femoris vein in here just like there's a proof under femoris so we're at the hip joint and deep within the hip joint there will also be some the circumflex arteries going around the hip so we'll also find some some circumflex veins doing the same sort of fingering but that is about it really it's not the other concepts then the the muscular venous pump so that idea of flow of blood from the superficial veins to the deep veins and then up and into the pelvis that flow is aided by the muscles contracting and relaxing so the muscles are within that fasciae latae that thick stocking so there they're kind of compressed already so as they contract and relax and contract and relax they squeeze the veins of that pressure change helps pull blood from the superficial veins into the deep veins member there's that one-way flow because of the valves and then helps push the blood up the lower limb in the deep veins as they get squeezed and push push push push and of course you've got the valves to help with that right so that is the muscular venous pump and we all notice that when we sat on long-haul flights or we sat around in lectures all day and our fingers get fat and on our feet kind of get fat and you kind of get a bit swollen and when we get up and we walk around there and that swelling that extra fluid starts to go away and that's partly because of that muscular venous pump brought up partly because the lymphatic system is also following the same route so movement helps draw the blood out of the lower limb and back into the torso so this is where the vein thrombosis DVT come in right a deep vein thrombosis so three things need to have really to make a clot more likely to form one of those things one of those factors is slow flow of the blood so you can see that if how if you're sat cramped up on a long-haul flight and you're not moving and your limbs your legs are beneath you so your heart still got to work against gravity to pull the blood up from your feet you can see how flow might slow down in these deep veins of the lower limb so a clot becomes more likely to form it's still somewhat uncommon but it does happen as we know now if a clot forms in a deep vein in the lower limb why is that so dangerous well blocking a blood vessel isn't a good thing anyway but if you block if you have a clot in a vein and then that clot breaks and you get a look of a clot flowing with the blood in the vein well as the vein ascends the lower limb it gets bigger and bigger and bigger so as it gets into as it gets back into the pelvis dammit we're missing bits but yeah it's pipe cleaners to the rescue the femoral vein is larger than the popliteal vein the external iliac vein is large the common iliac vein is large so the clot will flow through that quite happily and then we're into the inferior vena cava which runs up through the liver still nice and big no problems they're all run up through the inferior vena cava and the next place it gets to is the heart so the blood runs up into the heart and now it's in the right atrium nice big chamber run through the right atrium through the right atrioventricular valve into the right ventricle no problems at all through the valve up into the pulmonary trunk a nice big blood vessel ah and now we're into the arterial supply to the pulmonary trunk is going to split into left and right pulmonary arteries which will go into the lungs and then the pulmonary artery is going to split into lobar branches and branches branches branches but at that point the pulmonary arterial tree the the arteries are going to get smaller and smaller and smaller and smaller and smaller again so that clot that formed in the lower limb will flow up into the heart through the heart I think the pulmonary arterial tree quite happily but eventually it's gonna block one of those pulmonary arterial vessels and then it's blocking a blood flow to the lung right so now you've got a problem maybe it's a small clot and it might give almost no symptoms maybe it's a slightly larger clots it's blocking more of the pulmonary arterial tree and in case this exchange is impaired and you feel breathless you can't get enough air in you know and maybe you're starting to get a pleuritic pain so when you breathe deeply it hurts as well as you know only breathes shallowly because you've got a clot big enough to be irritating the pleura and now it's bad but maybe you've got a clot that's so big that it's actually blocking and of course it depends on your particular Anatomy as well because we're all different but if it's a clot that's big enough to block a significant amount of the arterial tree so if it's blocking you know an early part then it's not just preventing blood flow into that lung but it's also preventing blood flow out of the heart and it's also preventing blood flow back from that lung into the heart so now you are significantly compromising the cardiovascular system as a whole and you're affecting the heart and that could lead to cardiac arrest collapse unconsciousness and death so that's why a pulmonary embolism that forms in the lower limb can be so dangerous if you get symptoms in your calf you know the symptoms of a or signs of a deep vein thrombosis you might see a reddening of the skin it's most commonly in the calf a swelling pain maybe a deep aching pain then you should go and see your primary care provider ASAP go see your GP get checked out we often talk about deep vein thrombosis and the risk with long-haul flights but there are other associated other conditions with associated risks and the risk associated you know I mean there are other you know so it's it's not just in mobility there are other things as well that can cause a t vein thrombosis anyway right that's it the superficial veins and deep veins of the lower limb hopefully that was useful it's fairly straightforward in layers on top of your knowledge of the arterial supply to the lower limb so all right - I hope that was useful I'm gonna go get a snack now before I go home I'm gonna tidy this up away [Music]