Veins of the lower extremities
The venous system of the lower limbs of a person is represented by three systems: the system of perforating veins, the superficial and deep systems.
Perforating veins
The main function of the perforating veins is to connect the superficial and deep veins of the lower extremities. They got their name due to the fact that they perforate (penetrate) anatomical septa (fascia and muscles).
Most of them are equipped with suprafascial valves, through which blood flows from the superficial veins into the deep ones. About half of the communicating veins of the foot have no valves, so blood flows from the foot both from the deep veins to the superficial ones and vice versa. It all depends on the physiological conditions of the outflow and functional load.
Superficial veins of the lower extremities
The superficial venous system originates in the lower extremities from the venous plexuses of the toes, which form the venous network of the dorsum of the foot and the cutaneous dorsal arch of the foot. From it, the lateral and medial marginal veins begin, passing into the small and large saphenous veins, respectively. The plantar venous network connects to the dorsal venous arch of the foot, to the metatarsal and deep veins of the toes.
The saphenous vein is the longest vein in the body, containing 5-10 pairs of valves. Its normal diameter is 3-5 mm. A large vein begins in front of the medial ankle of the foot and rises to the inguinal fold, where it connects to the femoral vein. Sometimes a large vein in the lower leg and thigh can be represented by several trunks.
The small saphenous vein originates at the back of the lateral ankle and rises to the popliteal vein. Sometimes the small vein rises above the popliteal fossa and connects to the femoral, deep vein of the thigh or large saphenous vein. Therefore, before performing a surgical intervention, the doctor must know the exact place of the confluence of the small vein into the deep one in order to make an aiming incision right above the anastomosis.
The femoral-knee vein is a constant near-mouth inflow of the small vein, and it flows into the large saphenous vein. Also, a large number of subcutaneous and cutaneous veins flow into the small vein, mainly in the lower third of the leg.
Deep veins of the lower extremities
More than 90% of the blood flows through the deep veins. The deep veins of the lower extremities begin in the dorsum of the foot from the metatarsal veins, from where blood flows into the tibial anterior veins. The posterior and anterior tibial veins merge at the level of a third of the lower leg, forming the popliteal vein, which rises higher and enters the femoral-popliteal canal, already called the femoral vein. Above the inguinal fold, the femoral vein connects to the external iliac vein and is directed towards the heart.
Diseases of the veins of the lower extremities
The most common diseases of the veins of the lower extremities include:
- Phlebeurysm;
- Thrombophlebitis of superficial veins;
- Vein thrombosis of the lower extremities.
Varicose veins are a pathological condition of the superficial vessels of the small or large saphenous vein system caused by valvular insufficiency or venous ectasia. As a rule, the disease develops after twenty years, mainly in women. It is believed that there is a genetic predisposition to varicose veins.
Varicose veins can be acquired (ascending stage) or hereditary (descending stage). In addition, a distinction is made between primary and secondary varicose veins. In the first case, the function of deep venous vessels is not impaired, in the second case, the disease is characterized by deep vein occlusion or valve insufficiency.
According to clinical signs, there are three stages of varicose veins:
- Compensation stage. The legs show tortuous varicose veins without any other additional symptoms. At this stage of the disease, patients usually do not see a doctor.
- Subcompensation stage. In addition to varicose veins, patients complain of transient edema in the ankles and feet, pastiness, a feeling of distention in the leg muscles, rapid fatigue, and cramps in the calf muscles (mainly at night).
- Decompensation stage. In addition to the above symptoms, patients have eczema-like dermatitis and pruritus. With the advanced form of varicose veins, trophic ulcers and severe skin pigmentation may appear, resulting from small punctate hemorrhages and hemosiderin deposits.
Thrombophlebitis of superficial veins is a complication of varicose veins of the lower extremities. The etiology of this disease has not been sufficiently studied. Phlebitis can develop independently and lead to venous thrombosis, or the disease occurs as a result of infection and joins the primary superficial vein thrombosis.
The ascending thrombophlebitis of the great saphenous vein is especially dangerous, as there is a threat of the floating part of the thrombus entering the external iliac vein or deep vein of the thigh, which can cause thromboembolism in the vessels of the pulmonary artery.
Deep vein thrombosis is a rather dangerous disease and is a threat to the patient's life. Thrombosis of the main veins of the thigh and pelvis often originates in the deep veins of the lower extremities.
The following reasons for the development of venous thrombosis of the lower extremities are distinguished:
- Bacterial infection;
- Excessive exercise or injury;
- Prolonged bed rest (for example, for neurological, therapeutic or surgical conditions);
- Taking birth control pills;
- Postpartum period;
- DIC syndrome;
- Oncological diseases, in particular cancer of the stomach, lungs and pancreas.
Deep vein thrombosis is accompanied by swelling of the lower leg or the entire leg, patients feel a constant heaviness in the legs. With the disease, the skin becomes glossy, a pattern of saphenous veins clearly appears through it. The spread of pain along the inner surface of the thigh, lower leg, foot is also characteristic, as well as pain in the lower leg during dorsiflexion of the foot. Moreover, the clinical symptoms of deep vein thrombosis of the lower extremities are observed only in 50% of cases, in the remaining 50% it may not cause any visible symptoms.
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