The peroneal veins are deep blood-transporting vessels of the lower leg, meaning that they are found not near the skin but next to the shin bones, specifically to the fibula bone. They carry blood from lesser veins in the posterior and outer calf and themselves drain into a larger vessel called the posterior tibial vein. As veins, their purpose is to convey blood in the direction of the heart and lungs, blood depleted of nutrients by the many tissues in the leg that require it.
Also known as the fibular veins for their location adjacent to the fibula, the peroneal veins receive blood — via connecting vessels known as peroneal perforators — from the lesser saphenous vein. This is a superficial vein of the back of the calf, meaning that it sits close to the skin. Blood in the lesser saphenous comes from a network of tiny veins in the foot, and while it drains directly into the large popliteal vein in the back of the knee, it also diffuses into the peroneal veins via the peroneal perforators, veins that run between the vessels like the rungs of a ladder.
Blood in the peroneal veins also comes from the peroneal muscles, three muscles in the outer lower leg, as well as from other tissues found in what is known as the lateral compartment of the leg. The lower leg is divided into three compartments—anterior, posterior, and lateral, each of which is differentiated by its own network of nerves and blood vessels. Those smaller vessels in the lateral compartment drain into the peroneal veins, which in turn merge into a larger, single peroneal vein before emptying into the posterior tibial vein in the upper calf.
These veins function to send blood back to the heart when it has been depleted by the tissues in the leg. In other words, the muscles and other tissues remove oxygen, which they need to produce energy, as well as glucose, minerals like calcium and potassium, and a host of other nutrients and hormones from the blood. This depleted blood must be returned to the heart, which will cycle it to the lungs to pick up more oxygen; it also will receive nutrients from the digestive tract. The body’s arteries will then carry it back out to the body. For example, the peroneal artery brings this blood to the same muscles, skin, and other tissues that serve the peroneal veins.