In this article, I’ve tried to simplify the explanation of how varicose veins form to a basic level for everyone’s understanding.
Veins are the blood vessels of the body which generally speaking carry used blood from the body to the heart. Veins carry around 70% of total blood volume at any time. Veins are different from arteries. Arteries carry oxygenated blood from the heart to entire body.
Let us understand how veins work. Veins are like extensive pipelines spread throughout the body. If we were to imagine, we could compare the vein network in our body to the sewage systems in a city. Let’s say that after utilizing water in our houses for household purposes, the water is drained through the sewage pipes from our houses. Many such small sewage pipes from your neighbourhood carry wastewater into a bigger gutter / bigger sewage pipe. For understanding purposes only, we can compare this with the small veins called venules which transport used up blood (deoxygenated) on a microscopic level from tissues. And many small Venules combine to form a small Vein which then drain into bigger veins. The general flow of the blood in the veins (except a few) is from outside to inside, that is, from the furthest point of the body towards the heart.
The wall of the vein is very thin. It consists of 3 layers – internal (tunica intima), Middle (tunica media) and outer (Tunica Adventitia) layer. Compared to the arteries, the muscle layer is very thin. Also, veins have a one-way valve every few centimetres to prevent back-flow of blood. There are many valves in the veins, the important one are the ones at the main junction where usually two veins meet, especially where the outer veins enter in the deeper, main veins – directly or through small communicating veins. If you see the diagram of main veins in the legs, you’ll see that there are two types of major veins in the legs – Superficial and deep veins. Throughout the legs there are smaller communicating veins which connect the superficial veins and the deep veins. These communicating veins, also called perforators, have valves too, which transport blood from superficial vein to deep vein.
Now, the main reason of veins becoming dilated in the first place is the internal pressure of blood pressing on the walls of the vein. In a normal system, the blood keeps continuously flowing, all the valves are functioning properly so there’s no back flow of the blood and veins function smoothly. But if for some reason – maybe some kind of obstruction or destruction of these one-way valves or the pathway becomes defective due to any reason, the blood movement becomes slower, there’s back-flow and thus it becomes more difficult. This causes more blood to be collected in the lower smaller veins due to back flow & gravity. Since we know the muscle layer in the vein is very thin, the vein wall cannot hold on this pressure for a long time. Thankfully, since the veins are like a balloon rather than a fixed, hard pipe, they don’t burst immediately. The elastic walls of the vein become enlarged like a balloon. This in-turn causes problems to the vein segment near it. And as more and more part of the vein starts becoming dilated and eventually you see it from outside the skin when it is dilated enough. These ballooned up, snake-like veins are called Varicose veins. The common symptoms associated with varicose veins are – swelling of feet, swollen ankles, itching, restless legs, calf pain, dark pigmentation of skin, etc.
Varicose veins are a part of a larger venous disease group called – chronic venous insufficiency. In order to understand more about this, keep in touch with us through Facebook, Linkedin and our website where we’ll keep writing on different topics related to Vein health among other healthy living topics.