Today we're going to discuss the vessels of the lower limb. Our objectives here are to name the major vessels of the lower limb, describe the location of pulse points, and be able to differentiate between superficial and deep venous drainage. We start with the proximal blood supply. We remember that the aorta divides into right and left common iliac close to the fifth lumbar vertebra. The common iliac passes distally, divides into an external iliac and an internal iliac. Internal iliac becomes the artery of the pelvis, as well as the blood supply of the gluteal region. External iliac proceeds distally, and as it crosses deep to the inguinal ligament to enter the thigh, it becomes the femoral artery. We see that it's the same artery, but it changes its name as it passes from one region to another. That helps us pinpoint more precisely where a problem might exist. The femoral artery as it enters the thigh, branches into a deep femoral sometimes called the profunda femoral and the main femoral. The deep or profunda femoral becomes the main arterial supply of the thigh. The femoral artery itself has minimal contribution to the thigh itself and its major branches distally as we see supply the leg, the ankle, and the foot. Following, this set of images now require a little more detailed explanation. If we look at the anterior view, the artist has added a muscle here, the adductor magnus muscle. The reason we've done that is that as artery passes medially along the thigh, its course needs to carry it posterior to the knee. It does that through something called the adductor hiatus, a gap in the adductor muscle. As it passes through that adductor hiatus, we now look at a posterior view. We're now looking at the posterior part of the knee, we see the femoral artery here is now called the popliteal artery. Again, the same artery simply changes its name as it goes from one region of the extremity to the other. Just distal to the knee, the popliteal artery divides into a posterior tibial artery, which continues down the posterior leg. The anterior tibial artery, which passes between the tibia and the fibula to supply the anterior leg. We see here now on this lateral view, we see our posterior tibial artery passing down the posterior leg, and we see the anterior tibial, which is passed between the fibula and the tibia, to run down the anterior leg, where it continues distally on the dorsum of the foot as the dorsalis pedis artery. We remind ourselves here that the nomenclature for the foot is fairly complicated, but the dorsum of the foot is, if you're staring down at your foot, you're looking at the dorsum of your foot. The part of your foot that's on the ground is called the plantar surface. We stand on our plantar surface of our feet and we see the dorsal surface of our feet. This shows the posterior tibial artery passing around the medial malleolus onto the plantar surface of the foot. Again, where we stand as the medial and lateral plantar arteries. We now look at the veins. We see that there are set of veins, anterior and posterior tibial veins that travel with the anterior and posterior tibial arteries. We see quite often there are a pair of them, one on each side, often called an artery and its accompanying veins. Then superficially, we see a large vein, the great saphenous vein, which begins on the medial aspect of the foot, passes anterior to the medial malleolus, and drains superficially upwards of the extremity. The anterior-posterior tibial veins are the deep drainage. We see this superficial drainage does not have an accompanying artery. It's simply a venous channel that participates in the drainage of the lower extremity. This is now a posterior view of the knee. This is medial, this is lateral. Again, we see the popliteal artery and vein and some tributaries, but we see the great saphenous vein traveling up along the medial leg and along the medial thigh in the subcutaneous tissue unaccompanied by an artery. In the proximal thigh, we can see the femoral artery, femoral vein. At this point, the great saphenous vein joins the femoral vein. The femoral vein then passes deep to the inguinal ligament to become the external iliac vein. We remind ourselves now or think about pulse points. We always interested in where we can feel a pulse. As is often the case, it's where the vessels pass close to joints, are able to see things. The hip joint itself is right about here. We see just as the vessel's pass underneath the inguinal ligament onto the thigh we see the femoral triangle bounded by the inguinal ligament, the sartorius, and the adductor longus. We can see the femoral nerve, the femoral artery, the femoral vein from lateral to medial. This is a place where we can feel a femoral pulse. Posterior to the knee, and what's called the popliteal fossa. We can feel a popliteal pulse. The popliteal fossa is a roughly diamond-shaped structure, bounded superiorly by the hamstrings on each side, and the heads of the gastrocnemius. Within the popliteal fossa, we can feel a popliteal pulse. The popliteal artery, of course, is quite deep and dislocation, so it requires considerable effort to feel that pulse. At the ankle, again, we see the medial malleolus here, and we see that posterior tibial artery passing posterior to the medial malleolus along with the tendons that cross out onto the foot. This is a location of our posterior tibial pulse. On the dorsum of the foot between the tendency, the extensor hallucis longus, and the first slip of the extensor digitorum. In this space here between these tendons we can feel the dorsalis pedis artery or the dorsal artery of the foot on the dorsum of the foot. Now, we've thought about this, and I talked about the conventions that we use to discuss vessels as they pass from one region to another. Take a moment here, and try and put these vessels in order from proximal to distal, from the origin, from the aorta to this distal branch. I'll show you the answers shortly. We recall that the aorta divides into right and left common iliac. Then the common iliac divide into internal and external iliac. Internal iliac becomes the artery of the pelvis, and the external iliac continues to supply the lower extremity. As it passes deep to the inguinal ligament, we call it the femoral artery, passes down the thigh, passes posterior to the thigh through the adductor hiatus to become the popliteal artery, posterior to the knee. Then just distal to the knee. The popliteal artery divides into anterior, and posterior tibial arteries. The anterior tibial artery continues on the dorsum of the foot does the dorsalis pedis or the dorsal artery of the foot. Now, we talked about the importance of pulse points from a clinical point of view to determine if you're concerned about whether your patient is profusing their lower extremity. We think about places where we can feel a pulse. Which of these locations are pulse points? If you said all of these locations are pulse points, that's great. We call terminal triangles where we feel a femoral pulse. Popliteal fossa is where we feel a popliteal pulse. Dorsum of the foot as to where we feel a dorsal artery of the foot or the dorsalis pedis, and we feel a posterior tibial pulse posterior to the medial malleolus. Again, this is an important regional bit of information about where the arteries divide, and where you expect problems may occur. Where does the popliteal artery divide into anterior, and posterior tibial arteries. Now if you said inferior to the knee, that's exactly correct. The popliteal artery continues distally as the posterior tibial, but it gives off a branch that passes between the tibia, and the fibula to supply the anterior leg, and the dorsum of the foot. Here's a true-false question that saphenous artery accompanies the saphenous vein. If you said false, that's good because we remind ourselves that the saphenous vein is part of the cutaneous venous drainage of the lower extremity, and as such is not accompanied by an artery. Thank you. We look forward to seeing you at the next lecture.
