Take a look at the back of your hand, and you can probably trace a string of blue lines that lie just beneath your skin. As you likely know, these are your veins – and they serve a vital function in your cardiovascular system. Without them, deoxygenated blood would never make it back to the heart.
Sometimes, though, these little blue lines morph and take on completely different shapes and colors. Perhaps you have a dark red web of thin lines, or you might have noticed some of your veins twisting and turning. Either way, you see even more clearly through your skin now.