Overview_of_the_Lower_Extremity

Overview_of_the_Lower_Extremity - Overview of the Lower...

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Overview of the Lower Extremity Superficial Structures Veins The superficial veins of the lower extremity originate in the dorsal venous arch of the foot and empty into two superficial veins : great saphenous vein on the medial side of the foot, and the small saphenous vein on the lateral side of the foot. The greater saphenous vein ascends anterior to the medial malleolus, up the medial leg, posteromedial knee, and anteromedial thigh to pass through the saphenous hiatus (opening) in the fascia lata to empty into the femoral vein. It drains the dorsum of the foot, anterior leg, and anterior, lateral and medial thigh. The small (lessor) saphenous vein ascends posterior to the lateral malleolus, and up the middle of the posterior leg (deep to the crural fascia in the upper leg) to empty into the popliteal vein. Both veins have connections to the deep veins of the leg via perforating veins. Perforating veins convey blood from the superficial to the deep veins. Valves in the perforating veins prevent the backflow of blood from the deep veins into the superficial (greater and small saphenous) veins. Varicose veins are a result of failure of the valves of the perforating veins. Failure of these valves permits blood from the deep veins to backflow into the superficial veins. Due to the increased blood volume, the valves in the superficial veins fail, thus producing varicosities. Lymphatic drainage The superficial lymph vessels accompany the superficial veins, and terminate in the superficial inguinal lymph nodes. The lymph drains from these nodes into the external iliac lymph nodes, although some drains into the deep inguinal lymph nodes. The superficial inguinal nodes drain lymph from the superficial lower abdominal wall, external genitalia, perineum, buttocks and the lower limb. The deep lymphatic vessels accompany the deep veins of the leg, and drain into the deep inguinal lymph nodes. The deep inguinal lymph nodes (3 of them) are located in the femoral canal, medial to the femoral vein. Nerves below the knee The saphenous nerve is a branch of the femoral nerve. It accompanies the greater saphenous vein and provides cutaneous innervation on the anterior and medial side of the leg, and medial foot. The sural nerve is formed from both tibial and common fibular nerves. It accompanies the small saphenous vein and provides cutaneous innervation on the posterior and lateral aspects of the leg and lateral foot. The superficial fibular nerve which is a branch of the common fibular nerve provides cutaneous innervation of the inferior third of the anterior leg, and the dorsum of the foot. Fascia The deep fascia of the thigh is called the “fascia lata”. The deep fascia of the leg is called “crural fascia”. The fascia lata has 3 specializations in the thigh: 1) iliotibial tract which is a thick band that stretches along the lateral thigh from the iliac crest to the lateral condyle of the tibia; 2) lateral intermuscular septum which separates
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This note was uploaded on 02/17/2012 for the course MPAS PA 602 taught by Professor Dr.laird during the Fall '10 term at Chatham University.

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Overview_of_the_Lower_Extremity - Overview of the Lower...

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