The blood circulation in the legs consists of arteries, veins and capillaries. The arteries are high-pressure blood vessels that carry oxygen-rich blood from the heart. The arteries branch and divide into tiny capillaries, which deliver oxygen and nutrients to the tissues and carry away carbon dioxide and other metabolic waste products. The capillaries merge to form veins, which are low-pressure blood vessels that carry blood back to the heart.
Arterial Leg Circulation Anatomy
The legs receive arterial blood supply from the large femoral arteries, which enter the leg at the front of the hip, notes Grant's Atlas of Anatomy. The femoral artery branches within the leg, giving rise to several other arteries, including the superficial and deep femoral arteries in the thigh, the popliteal artery near the knee and the anterior and posterior tibial arteries in the lower leg. Several smaller arteries supply the muscles and tissues of the foot.
Venous Leg Circulation Anatomy
The venous circulation of the leg includes interconnected superficial and deep networks of veins, which empty into the large femoral vein. The femoral vein, which is part of the deep venous system, sits next to the femoral artery at the front of the hip. Grant's Atlas of Anatomy notes that other deep veins of the leg include the popliteal and tibial veins of the knee and lower leg, respectively. The great saphenous vein, part of the superficial venous system, spans the length of the leg on the inner aspect of the calf and thigh. The small saphenous vein rests in the superficial tissue of the calf.
Problems with the Arterial Leg Circulation
Problems with the arterial circulation of the legs can deprive the leg muscles of the oxygen needed to function. Peripheral arterial disease occurs when atherosclerotic plaques--areas of fatty buildup in the arteries--partially obstruct oxygen-rich blood flow to the legs. Common symptoms of peripheral arterial disease include exercise-induced muscle pain, weakness or heaviness in the legs, reports the Baylor College of Medicine Department of Surgery. The leg pain, known as intermittent claudication, characteristically resolves with rest. Severe peripheral arterial disease may cause foot pain at rest. Poor arterial circulation in the legs increases the risk for chronic leg ulcers, which may lead to serious infections necessitating amputation.
Problems with the Venous Leg Circulation
Several problems of varying severity can occur in the venous leg circulation. Malfunction of the one-way valves of the leg veins commonly cause varicose veins, abnormally distended superficial leg veins. Varicose leg veins may develop blood clots, known as superficial venous thrombosis, reports the Merck Manuals Online Medical Library. Blood clots in the deep venous system of the leg, or deep venous thrombosis, are a concerning medical problem because part of the clot may dislodge and travel to the lungs. This condition, known as a pulmonary embolism, can prove life-threatening.
Modifiable Risk Factors
Smoking remains the leading risk factor for the development of problems with the arterial circulation of the legs, reports the National Heart Lung and Blood Institute. Overweight, obesity and lack of physical activity increase the risk for the development of deep vein thrombosis.
References
- "Grant's Atlas of Anatomy, Tenth Edition"; Anne M. R. Agur, Ph.D., et al., Editors; 1999
- Baylor College of Medicine Department of Surgery: Peripheral Arterial Disease
- Merck Manuals: Superficial Venous Thrombosis
- Merck Manuals: Deep Venous Thrombosis (DVT)
- National Heart Lung and Blood Institute: Who Is At Risk for Peripheral Arterial Disease?
