In the body oxygen is transported through the blood vessels. Oxygen-rich blood from the lungs is circulated by the heart to the brain and the rest of the body by large arteries. These arteries split and get smaller. At the place of destination (in the body) there should be a transfer taking the place of oxygen and nutrients. The blood flow may, of course, not be too fast, otherwise this transfer does not take place. Because the arteries so frequently have split and ever have narrowed blood eventually flows very slowly. The small vessels where this transfer of oxygen and nutrients takes place are the capillaries (capillaries). Eventually it becomes oxygen-poor blood again collected in small vessels which come back together and get bigger; the veins. The veins transport the oxygen-poor blood back to the heart.
A capillary malformation is a departure from the capillaries. These vessels are then usually widened, making you the typical color of this skin condition. A capillary malformation is a slow-flow vascular malformation. Examples include the Wine Stain (Nevus flammeus), Stork bite and Cutis Marmorata Telangiectatica Congenita (CMTC).