👉 Cap veins are small, thin-walled blood vessels that connect the superficial veins to larger veins beneath the skin's surface. They are usually found in areas where the skin is thinner, such as the face and neck, and allow for easier drainage of blood from these regions. Cap veins can become visible on the skin's surface when they become dilated or inflamed, often appearing as blue or purple spots. They play a role in regulating blood flow and pressure in the superficial venous system, but can sometimes contribute to varicose veins if their function is impaired.