The fibular vein is one of several blood vessels, perhaps better known in anatomy as the peroneal veins, transporting blood up the leg from the outer aspect of the calf. A deep vein of the leg, this vessel and its counterparts are found in the very center of the limb to the inside of the fibula bone, one of two long bones of the lower leg. Each fibular vein is fed by multiple smaller veins of the lateral compartment of the leg, vessels that return blood that has delivered oxygen, glucose, and other nutrients to the peroneal muscles and their accompanying tissues. This blood is then deposited by the fibular veins into the posterior tibial veins and subsequently the popliteal vein, which will carry it back up the thigh toward the heart.
In the lower leg, multiple large vessels transport blood between the tissues found here and the heart. Arteries carry blood containing nutrients and oxygen from the heart to the tissues, and veins return it to the heart once these nutrients have been depleted by the tissues. These tend to occur in pairs and in the lower leg include the popliteal artery and vein, the anterior tibial artery and veins, the posterior tibial artery and veins, and the fibular artery and its corresponding veins, among others.
While arteries transport blood from larger to smaller vessels and its branches tend to be known by other names, a vein under a single name may include two or more smaller vessels returning blood to one larger vein. These are known as venae comitantes, and they run to either side of their corresponding artery. The fibular veins, then, accompany the fibular artery before uniting to form a single fibular vein and delivering blood to the posterior tibial veins, which are the venae comitantes of the posterior tibial artery.
Each fibular vein, in addition to receiving blood from smaller vessels returning from the peroneal muscles on the lateral side of the calf, is fed by a closed loop of veins in the foot. Blood from these veins travels through every major vein of the lower leg on its course back to the heart, with veins growing in size the higher in the leg they are found. For instance, the fibular veins merge to form a larger fibular vein, which then merges with the posterior tibial vein to form the larger tibial/peroneal trunk a short distance beneath the knee joint. The posterior tibial vein then joins the anterior tibial vein behind the knee to form the popliteal vein, one of two major veins of the thigh.