Blood Supply and Anastomosis of Lower Limbs

Blood Supply and Arterial Anastomosis of the Lower Limbs, Venous and Lymphatic Drainage

• The abdominal aorta divides into the right and left common iliac arteries.

• The common iliac arteries subdivide into internal and external iliac arteries.

• The external iliac arteries become femoral arteries in the thighs, transitioning to popliteal arteries behind the knee, and finally to anterior and posterior tibial arteries in the legs.

• The common iliac arteries, located at the level of the fourth lumbar vertebra, divide into internal and external iliac arteries, supplying the pelvis, external genitalia, and lower limbs. Each passes about 5 cm inferiorly.

• The internal iliac arteries (hypogastric arteries) are the primary arteries of the pelvis, starting at the bifurcation of the common iliac arteries. They run posteromedially and divide into anterior and posterior divisions, supplying the pelvis, buttocks, external genitalia, and thigh.

• External iliac arteries are larger than internal iliac arteries, originating at the bifurcation. They descend along the psoas major muscle, passing posterior to the inguinal ligaments, becoming femoral arteries. The external iliac arteries supply muscles of the anterior abdominal wall, cremaster muscle in males, and round ligament of the uterus in females, along with the lower limbs.

• Femoral arteries descend along the anteromedial aspects of the thighs, passing through the adductor magnus muscle tendon into the popliteal arteries posterior to the femur. A pulse can be felt in the femoral artery just inferior to the inguinal ligament. Femoral arteries serve the lower abdominal wall, groin, external genitals, and muscles of the thigh.

• The popliteal artery directly continues from the superficial femoral artery as it exits the adductor canal. It enters the popliteal fossa, running posteriorly behind the knee. Branches include inferior medial and lateral genicular arteries, circulating around the tibial condyles as part of the genicular anastomosis. The middle genicular artery pierces the oblique popliteal muscle, supplying hamstrings, adductor magnus, and triceps surae. Cutaneous branches supply skin over the knee.

• Anterior tibial arteries descend through the anterior muscular compartment of the leg, passing between the tibia and fibula through the interosseous membrane. They supply the knee joints, anterior compartment muscles, and the skin of the anterior leg and ankle joints. Anterior tibial arteries on the foot's dorsum branch into arcuate arteries, supplying the metatarsals. Arcuate arteries branch further into dorsal metatarsal arteries, supplying the foot, and finally, into dorsal digital arteries, supplying the toes.

• Posterior tibial arteries are a direct continuation of the popliteal arteries, passing down the posterior muscular compartment of the leg behind the medial malleolus. They branch into medial and lateral plantar arteries. Medial plantar arteries supply the abductor hallucis and flexor digitorum brevis muscles, while lateral plantar arteries join a dorsal artery branch to form the plantar arch, providing plantar metatarsal arteries and ending in plantar digital arteries supplying the toes.

• Deep veins run parallel to arteries. Superficial veins have many anastomoses.

• The chief superficial veins are the great and small saphenous veins. The great saphenous vein originates on the medial side of the dorsal venous network of the foot. It runs upward, anterior to the medial malleolus, accessible for catheterization.

• The small saphenous vein begins on the lateral aspect of the dorsal venous arches of the foot, passing posterior to the lateral malleolus, and continues deep to the skin along the posterior aspect of the leg, emptying into the popliteal fossa.

• Deep veins include posterior tibial, anterior tibial, and femoral veins.

• The popliteal veins are formed by the union of the anterior and posterior tibial veins and receive blood from small saphenous veins and tributaries.

• The lymphatic drainage of the lower limb is arranged with superficial lymphatic vessels forming medial trunks, ending in inguinal nodes or merging with medial trunks superior to the knee; a lateral set is present. Popliteal nodes receive deep lymphatic trunks accompanying tibial blood vessels.

• The inguinal nodes lie both longitudinally along the great saphenous vein and transversely, just inferior to the inguinal ligament. Deep inguinal nodes lie medial to the femoral vein.

• When the inguinal nodes are enlarged, examination includes the area inferior to the umbilicus. Efferent lymphatic vessels from inguinal nodes lead to external iliac and lumbar (aortic) nodes.

This quiz focuses on the blood supply and arterial anastomosis of the lower limbs, including the abdominal aorta, common iliac arteries, and their branches. It also covers the venous and lymphatic drainage systems. Test your understanding of these vascular structures and their functions in the human body.