The fibula (calf bone) is one of the two long bones that comprise the leg. It is thinner than the other bone in the leg called the tibia (shin bone). Moreover, the fibula lies parallel and lateral to the tibia. The two bones are connected to each other through an interosseous membrane, by which they form a syndesmosis joint.
Both upper and lower ends of the fibula are attached to the tibia through ligaments. Its lower end slightly inclines forward projecting below the tibia, which forms the lateral portion of the ankle joint. Meanwhile, the upper end of the fibula is attached posteriorly to the head of the tibia and inferior to the knee joint. Therefore, the fibula has nothing to do with the formation of the knee-joint.
The parts of the fibula include:
1. Shaft or body of the fibula
2. Interosseous membrane- a connective tissue that attaches the fibula to the tibia
3. Superior tibiofibular articulation (joint of the head of the tibia and fibula)
4. Inferior tibiofibular articulation (joint of the lower end of the tibia and fibula)
The Functions of the Fibula and Bone Grafting
Primarily, the fibula serves as attachment for the skeletal muscles in the leg. It does not bear the body weight like the tibia does because it is slender. In fact, the tibia can support the body weight even without the fibula. Consequently, the fibula is often safely harvested and is used in bone grafting, surgical procedure of transplanting bone tissues to replace fractured or diseased bones. Usually, the fibula is used in reconstructing the mandible (lower jaw).
In bone grafting, the blood supply of the fibula is always significantly considered because it’s a major factor for the survival of the bone graft. The fibular artery supplies blood, nutrients, oxygen and other essential substances to the middle third of the fibular shaft. This is why the middle third of the fibular shaft is commonly harvested for bone graft. The blood vessel that supplies blood to the fibula, particularly to its head and epiphysis, is the anterior tibial artery.