Anatomy: Blood Supply of the Lower Limb PDF

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Complete circulatory demonstration to the lower limb in humans. ...

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Paul Tierney; 26/11/08

Blood supply of the lower limb The main arterial stem of the lower limb is the femoral artery, which undergoes name changes on its descent The exception is the gluteal region, which is served by superior and inferior gluteal arteries from the internal iliac artery of the pelvis Femoral artery This is a continuation of the external iliac artery, which changes its name when it passes under the inguinal ligament Course -- This main artery enters the thigh under the inguinal ligament in the femoral sheath, with the femoral vein and canal medial to it -- Deep to the inguinal ligament it may be compressed against the pubic bone -- The femoral sheath ends 2 cm distal to the inguinal ligament -- The neurovascular bundle runs through the femoral triangle to its apex, to enter the adductor canal -- The artery and vein are suitable for catherisation and puncture in the femoral triangle -- The artery exits the canal distally through the hiatus in adductor magnus, where it changes its name to the popliteal artery Branches x Profunda femoris x Muscular branches

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x x x x x x

Paul Tierney; 26/11/08

Superior circumflex iliac ½ Superior epigastric ¾ Not involved in limb Superior external pudendal ¾ blood supply Deep external pudendal ¿ Articular branches to knee Occasionally medial and lateral circumflex iliacs

Profunda femoris -- This artery is the main supply to structures in the thigh -- It arises approximately 4cm below the inguinal ligament -- It supplies most of the muscles of the thigh through four perforating branches, but also directly -- Its most important branches are the lateral and medial circumflex femoral arteries, which supply the hip joint, and which may arise from the femoral artery directly Lateral circumflex femoral x This artery is given off the lateral side of the profunda femoris x Passes posterolaterally between the branches of the femoral nerve x Gives off an ascending branch to the trochanteric anastomosis x Gives off a transverse branch to the cruciate anastomosis x A descending branch reinforces the anastomosis of the knee x Muscular branches are to sartorius, tensor fascia lata, rectus femoris, vastus lateralis, vastus intermedius and vastus medialis

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Paul Tierney; 26/11/08

Medial circumflex artery -- Given off profonda femoris artery above the level of lateral circumflex, or from the femoral artery directly -- Smaller than the lateral circumflex, it is more important for supply of the head of the femur -- Passing posteriorly between pectineus and the psoas tendon, it runs between adductor brevis and obturator internus firstly, then between quadratus femoris and adductor magnus to enter the gluteal region, giving branches to all these muscles -- Gives off an ascending branch to the trochanteric anastomosis -- Gives off a transverse branch to the cruciate anastomosis Perforating arteries x These are terminal branches of the profonda femoris artery x Four arise in series from this artery and run medially x They pierce adductor magnus near the linea aspera, and pass posterior to the femur to supply the hamstring muscles x They end by anastomosing in the substance of vastus lateralis x The first sends a branch to cruciate anastomosis, 2nd or 3rd supplies a nutrient artery to the femur and 4th sends a branch to the knee anastomosis Popliteal artery -- The continuation of the femoral artery, distal to the adductor hiatus -- Ends at the inferior border of popliteus muscle where it divides into anterior and posterior tibial arteries -- It passes through the middle of the popliteal fossa -- Gives off 5 genicular branches to the knee joint -- Gives off sural arteries to gastrocnemius muscles -- Other muscular branches are to hamstrings and calf muscles

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Paul Tierney; 26/11/08

Branches -- Superior and inferior, medial and lateral genicular arteries supply the knee anastomosis and joint capsule -- The middle genicular artery supplies the intercondylar notch -- Sural arteries are end arteries; if these arteries are cut, ischaemic necrosis of the gastrocnemius muscle results -- Popliteal divides into terminal branches above interosseous membrane to supply extensor and flexor compartments of leg Anterior tibial artery x This is a terminal branch of the popliteal artery x Runs anteriorly over the interosseus membrane to descend on the membrane with the deep peroneal nerve, to supply the muscles of the extensor compartment of leg x Passes anterior to the ankle joint where it is renamed the dorsalis pedis artery x Its arcuate branch forms the dorsal metatarsal arterial arch of the foot Posterior tibial artery -- Continuation of the popliteal artery, which passes deep to the soleal arch into the flexor compartment of leg (calf) -- Gives rise to the peroneal artery -- It runs with tibial nerve on the fibular aponeurosis of flexor digitorum longus, supplying a large nutrient artery to the tibia and muscles of ‘calf’ -- Passes posterior to the medial malleolus and ends by dividing into

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Paul Tierney; 26/11/08

medial and lateral plantar arteries under the flexor retinaculum Peroneal artery x Largest branch of the posterior tibial artery x Lies medial to fibula in ‘tunnel’ of flexor hallucis longus x Gives branch through flexor digitorum aponeurosis to tibialis posterior and also supplies nutrient artery to the fibula x Other muscular branches wind posterior to fibula to supply peroneal muscles x The peroneal artery ends by giving a perforating branch that pierces the interosseous membrane to supply the extensor compartment and a lateral calcaneal branch to the lateral malleolus and heel Medial & lateral plantar arteries -- These are the terminal branches of the posterior tibial artery -- They form deep to the flexor retinaculum of the ankle -- Supply muscular branches to small muscles of sole of foot -- Deep branch of lateral plantar artery forms plantar arterial arch of sole Plantar arterial arch x Formed by deep branch of lateral plantar artery and completed by deep artery from dorsalis pedis x The arch lies between layers 3 and 4 of the sole x It connects with the dorsal arch through perforating arteries x Supplies toes by common and proper plantar digital arteries, analogous to hand

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Paul Tierney; 26/11/08

Dorsal arterial arch -- Formed by arcuate branch of dorsalis pedis artery, reinforced by perforating arteries from the sole -- Gives off dorsal metatarsal and dorsal digital arteries, which supply dorsum of the toes to nail beds

Venous drainage This is a similar system to the upper limb venous drainage x Veins of sole and deep muscles drain dorsally (‘sole pump’) x A dorsal venous arch collects blood from this sole pump x Digital veins pass along dorsal margins of web spaces into this arch x Superficial veins drain this venous arch proximally x Generally, the great saphenous vein drains the anteromedial area of leg and the small saphenous vein drains the posterolateral area x In the leg, perforators pass from superficial to deep veins, especially to the soleus plexus (‘soleus pump’) in the calf x These deep veins are at risk from deep vein thrombosis (DVT) x Muscle contraction pumps deep blood through popliteal and femoral veins into the external iliac vein x These veins are all valved to prevent back flow either distally or superficially x Valve incompetence leads to varicose veins

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Paul Tierney; 26/11/08

Great saphenous vein -- This is the longest vein in the body and it runs superficially -- Of importance due to formation of varicosities in it -- Favourite vein for use as a graft, often arterial; also for cut downs, for emergency intravenous fluids administration -- Many valves exist along its course, and it has many connections to deep veins -- Receives four inguinal tributaries before emptying into the femoral vein; superficial circumflex iliac, superficial epigastric, superficial and deep external pudendal veins Small saphenous vein x Drains the posterolateral aspect of the ankle and leg, but does not drain the sole (see above) x It passes up the back of the leg to empty into the popliteal vein in its fossa Lymph drainage -- Lymph may drain superficially or deep; superficial drainage is with the veins, deep drainage is with the arteries -- Division between superficial and deep is the fascia lata -- There are also subcutaneous channels, but these are short, and end in a vein -- Most superficial lymph drains in vessels accompanying the great saphenous vein, to inguinal lymph nodes -- Lymphatics with the small saphenous vein drain a small area of skin around the heel and empty into popliteal nodes -- Deep structures drain via lymph vessels travelling with arteries, some of which pass through popliteal lymph nodes, but most draining directly into deep inguinal nodes -- Lymph channels are valved like veins to prevent retrograde flow

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Paul Tierney; 26/11/08

Inguinal lymph nodes x Superficial inguinal nodes are described as proximal and distal groups and the former into medial and lateral groups x The distal group receives all superficial lymphatics from the limb except those from the posterolateral calf x The medial group receives lymph from umbilicus and anterior abdominal wall below it, external genitalia in both sexes (excl. testes), lower anal canal, perineum and a small part of the uterus (via round ligament) x The lateral group receives lymph from the buttock, flank and back below the waist x All superficial nodes drain to external iliac nodes, some via femoral canal, and others anterior or lateral to femoral vessels x Deep inguinal nodes are situated medial to femoral vein and drain to external iliac nodes Clinical Femoral artery occlusion at adductor hiatus DVT/ thrombophlebitis/ pulmonary embolus Varicose veins Ascending lymphangitis/ inguinal node enlargement Intermittent claudication/ dorsalis pedis pulse Posterior tibial pulse Gangrene of digits...