Vasculature of Lower limb PDF

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Summary

A thorough guide through the entire vasculature of the lower limb. Starting from the the femoral artery to all the small arteries of the foot. Also, taking about the superficial and deep veins of the lower limb, with clinical information provided. ...

Description

Vasculature of Lower limb Arterial supply 

Femoral artery The main artery of the lower limb is the common femoral artery. It is a continuation of the external iliac artery. The external iliac becomes the femoral artery when it crosses under the inguinal ligament and enters the femoral triangle on the anterior aspect of the thigh of the upper thigh. The common femoral artery gives off the profunda femoris artery and becomes the superficial femoral artery to descend along the anteromedial part of the thigh in the femoral triangle (4cm below the inguinal ligament). It travels posteriorly and distally, giving off three main branches: medial circumflex artery, lateral circumflex artery and 3-4 small perforating branches. Th medial circumflex artery has 2 branches, one branch ascends to the trochanteric fossa + connects with branches of the gluteal and lateral circumflex arteries the other branch passes laterally to form an anastomotic network around the hip joint. Supplying the head + neck of the femur. It travels posteriorly and distally, giving off three main branches. In a fracture of the femoral neck this artery can easily be damaged, and avascular necrosis of the femur head can occur. The lateral femoral circumflex artery passes deep to Sartorius and rectus femoris and gives off 3 branches: Ascending branch, Descending branch and transverse branch. These all wrap around the anterior and lateral side of femur and supply muscles on the lateral aspect of the thigh. The small perforating arteries consisting of three or four arteries that perforate the adductor magnus, contributing to the supply of the muscles in the medial and posterior thigh. The superficial femoral artery continues down the anterior surface of the thigh, via a tunnel known as the adductor canal. During its descent, the artery supplies the anterior thigh muscles. The adductor canal ends at an opening in the adductor magnus, called the adductor hiatus and enters the posterior compartment of the thigh, proximal to the knee. The femoral artery now known as the popliteal artery. The descending genicular artery (most superior of genicular arteries) arises from the femoral artery just before it passes through the adductor hiatus.  As the femoral artery can often be palpated through the skin, it is often used as a catheter access artery. From it, wires and catheters can be directed anywhere in the arterial system for intervention or diagnostics, including the heart, brain, kidneys, arms and legs (coronary angiography: Femoral artery is catheterized in a long thin, tube. Tube is navigated up through the external iliac, common iliac, aorta and into coronary vessels. A radio-opaque dye is injected into the coronary vessels and visualized by x-ray). The direction of the needle in the femoral artery can be against blood flow (retro-grade), for intervention and diagnostic towards the heart and opposite leg, or with the flow (ante-grade or ipsi-lateral) for diagnostics and intervention on the same leg. The site for optimally palpating the femoral pulse is in the inner thigh, at the mid-inguinal point, halfway between the pubic symphysis and anterior superior iliac spine.

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Popliteal artery  The popliteal artery is a deeply placed continuation of the femoral artery after it passes through the adductor hiatus, or opening in the distal portion of the adductor magnus muscle. It courses through the popliteal fossa and passes obliquely through the popliteal fossa and then travels between the gastrocnemius and popliteal muscles of the posterior compartment of the leg, where it ends. As it continues inferiorly, it passes under the fibular and tibial heads of the soleus muscle and immediately bifurcates into the anterior and

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anterior tibial artery and the tibioperoneal trunk. The tibioperoneal trunk then divides into the posterior tibial and fibular arteries. The deepest (most anterior) structure in the fossa, the popliteal artery runs in close proximity to the joint capsule of the knee. Despite its short course, the popliteal artery has several branches: The sural arteries are large vessels that arise on each side of the popliteal artery to provide a vascular supply to the gastrocnemius, soleus and plantaris muscle. The popliteal artery gives off five genicular branches that contribute to the periarticular genicular anastamosis that supply the knee joint capsule and ligaments. The five branches are: Superior lateral genicular artery, Superior medial genicular artery, Middle genicular artery, Inferior lateral genicular artery & Inferior medial genicular artery. The anterior tibial artery, passes anteriorly between the tibia and fibula, through the interosseous membrane. Carries blood to the anterior compartment of the leg and continues to the dorsum of the foot to become the dorsalis pedis artery. Accompanied by the anterior tibial vein along its course. The posterior tibial artery continues inferiorly, along the surface of the deep muscles (such as tibialis posterior). It accompanies the tibial nerve in entering the sole of the foot via the tarsal tunnel. The fibular artery moves laterally from its point of origin, penetrating the lateral compartment of the leg. It supplies muscles in the lateral compartment, and adjacent muscles in the posterior compartment. It is accompanied by a deep vein, the posterior tibial vein, along its course.  Although the popliteal artery is difficult to palpate (as it runs deep within the popliteal fossa) a popliteal pulse can be felt. This can be achieved with the patient in a lying position with their knee up and flexed so that the popliteal fascia and hamstrings are relaxed. The pulsing of the popliteal artery can then be felt at the inferior aspect of the popliteal fossa. This is important since a weak or absent popliteal pulse may indicate obstruction of the femoral artery and vascular compromise. Popliteal Artery Entrapment Syndrome (PAES), The popliteal artery runs between the two heads of the gastrocnemius muscle of the leg. Any variations that occur here can lead to intermittent claudication (pain due to insufficient blood supply) during muscle contraction. This leads to repetitive trauma to the popliteal artery which in turn may result in arterial thrombosis and thromboembolism or formation of aneurysms. The posterior tibial artery pulse csn be palpated at Pimenta’s point. An imagined line is drawn between the bony prominence of the medial malleolus and the insertion of the Achilles tendon. At the exact midpoint of this line place three fingers parallel to the leg and you will either feel the posterior tibial pulsation (normal) or will not (peripheral vascular disease).

Dorsalis pedis artery It arises at the anterior aspect of the ankle joint and is a continuation of the anterior tibial artery. It terminates at the proximal part of the first intermetatarsal space, where it divides into two branches, the first dorsal metatarsal artery and the deep plantar artery. The dorsalis pedis communicates with the plantar blood supply of the foot through the deep plantar artery. The dorsalis pedis artery supplies the tarsal bones and the dorsal aspect of the metatarsals. Dorsalis pedis artery can be palpated from a point mid-way between the malleoli to the cleft between the first and second metatarsals and lateral to the extensor hallucis longus tendon (or medially to the extensor digitorum longus tendon) on the dorsal surface of the foot.

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Plantar arteries The posterior tibial artery on the other hand, enters the foot via the tarsal tunnel, winding behind the medial malleolus, and then it splits into the lateral and the medial plantar arteries, which are present on the plantar aspect of the foot. The lateral plantar artery is much larger that the medial one. These arteries supply the plantar side of the foot, and contributes to the supply of the toes via the deep plantar arch (where the lateral unites with the deep plantar branch of the dorsalis pedis artery, thus completing the plantar arch).

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Obturator artery Originates as a branch of the internal iliac artery in the pelvic cavity. Enters medial compartment of the thigh through the obturator canal. As it goes through the canal, bifurcates into an anterior + posterior branch. Anterior branch supplies pectineus, obturator externus, adductor muscles and gracilis. Posterior branch supplies some deep gluteal muscles. Acetabular vessel originates from the posterior branch, enters hip joint through the acetabular notch and contributes to head of femur.

Venous drainage The veins of the lower limb drain deoxygenated blood and return it to the heart. They can be divided into two groups – deep and superficial. Deep veins are located underneath the deep fascia of the lower limb, accompanying the major arteries. Superficial veins are found in the subcutaneous tissue. They eventually drain into the deep veins. 

Deep veins They are located within a vascular sheath with the corresponding artery, which helps compress and move blood within the veins. Both types of veins contain venous valves, to prevent reflux of blood distally, but they are more numerous in the deep veins. They also contain tributaries, other veins which drain into them. The main venous structure of the foot is the dorsal venous arch, which mostly drains into the superficial veins. Medial and lateral plantar veins arise from this arch. These veins combine to form the posterior tibial and fibular veins. The posterior tibial vein accompanies the posterior tibial artery, entering the leg posteriorly to the medial malleolus. Veins from the calf muscles drain into posterior tibial veins. The anterior tibial veins are formed by the venae comitantes, or companion veins, of the dorsalis pedis vein. On the posterior surface of the knee, the anterior tibial, posterior

tibial and fibular veins unite to form the popliteal vein. The popliteal vein enters the thigh via the adductor canal.

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The popliteal vein usually has 4 or 5 valves and many tributaries. All of the three main veins of the leg drain into it, as well as the short saphenous vein and two muscular veins from each head of the gastrocnemius muscle ( gastrocnemius vein). The femoral vein is a continuation of the popliteal vein and accompanies the femoral artery. It begins at the opening of the adductor magnus muscle and ends posterior to the inguinal ligament as the external iliac vein. Its relationship to the femoral artery is variable. Within the distal adductor canal, it is located posterolateral to the artery, whilst in the proximal canal and in the apex of the femoral triangle, it lies posterior to the artery. Within the base of the femoral triangle, it is found medial to the femoral artery. It is contained within the middle compartment of the femoral sheath and usually has four or five valves. Tributaries of the femoral vein include: the medial circumflex vein, lateral circumflex vein, long saphenous vein & profunda femoris vein. The deep vein of the thigh (profunda femoris vein) is the other main venous structure in the thigh. Via perforating veins, it drains blood from the thigh muscles. It then empties into the distal section of the femoral vein.

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Superficial veins Two major superficial veins – the great saphenous vein, and the small saphenous vein  Great saphenous vein: Longest vein in the human body. It is a continuation of the medial marginal vein of the foot and ascends superficial to the medial malleolus, it passes behind the medial tibial and femoral condyles before ascending up the medial aspect of the thigh and passing through the saphenous opening, an aperture in the fascia lata of the thigh. The long saphenous vein is accompanied by branches of the medial femoral cutaneous nerve throughout its course in the thigh. Terminates by draining into the femoral vein 2.5 – 3.5 cm inferolateral to the pubic tubercle. It forms an arch, the saphenous arch, to join the common femoral vein in the region of the femoral triangle at the sapheno-femoral junction. As the vein moves up the leg, it receives tributaries from other small superficial veins.  The vein is often removed by cardiac surgeons and used for auto transplantation in coronary artery bypass operations, when arterial grafts are not available or many grafts are required, such as in a triple bypass or quadruple bypass. he great saphenous vein is the conduit of choice for vascular surgeons, when available, for doing peripheral arterial bypass because it has superior long-term patency compared to synthetic grafts, human umbilical vein grafts or biosynthetic grafts. Removal of the saphenous vein will not hinder normal circulation in the leg. The blood that previously flowed through the saphenous vein will change its course of travel. This is known as collateral circulation. The saphenous nerve is a branch of the femoral nerve that runs with the great saphenous vein and can be damaged in surgery on the vein.  Small saphenous vein: Is a continuation of the lateral marginal vein. It passes lateral to the calcaneal tendon (inferior and posterior to the lateral malleolus) and ascends on the posterior surface of leg (superficial fascia) along with the sural nerve. Penetrates the deep fascia between the 2 heads of the gastrocnemius muscle and it terminates in the popliteal vein within the popliteal fossa, 3- 7.5 cm above the knee

joint. Sometimes there’s a variant, instead of instead of draining in the popliteal vein it can merge with the Giacomini vein (communicant vein between the great saphenous vein (GSV) and the small saphenous vein(SSV) and drain in the GSV at the superior 1/3 of the thigh....