The fibula is the long, thin bone of the lower leg on the side of the little toe. It runs parallel to the tibia or shin bone and plays a significant role in stabilizing the ankle and supporting the muscles of the lower leg. It is about the same size when compared with the tibia, but it is considerably thinner. The thickness corresponds to the varying roles of the two bones. The tibia bears the body weight from the knees to the legs whereas the fibula functions as a support for the tibia to stabilize weight. Many muscles of the thigh and lower leg attach to the fibula through the tendons. The fibula can also be harvested for tissue to graft onto other bones in the body. The fibula can get damaged due to various factors, such as a fracture. The fibula usually takes about three to six months to heal. Healing depends on many factors, such as age, vitamin D levels and the type of fracture. The healing may be faster by getting adequate rest, not putting too much weight on the leg and following the doctor’s care instructions.
Basic anatomy of the fibula
The fibula is located just behind the tibial head at the knee joint and then runs down until it reaches the ankle joint. The fibula and tibia are connected by a tissue sheet called the ridge on the medial surface of the fibula, which forms the interosseous membrane. The structure of the fibula can be broken down into the head, neck, shaft (body) and distal end of the fibula. As the head becomes narrow distally, the fibular neck is formed. The shape of the fibular shaft is determined by the muscle attachments. The distal (far) end of the fibula forms the ball of the ankle, which stays in contact with the bones in the foot.
Functions of the fibula
The fibula is one of the paired bones of the lower legs of humans. It connects with the tibia through appropriate articulation and ligaments. The fibula is the slender long bone in the body, considering its ratio of width to length. Some of the main functions of the fibula include
- It is not a weight-bearing bone. The main function is to combine with the tibia and provide stability to the lower limb and ankle joint.
- The distal end of the fibula has several grooves for ligaments attachments that stabilize and provide leverage during ankle movements.
- The lateral ligament attached to the fibular head provides knee stability.
- The fibula is often used as a donation site for bone grafts to repair bony structures in other parts of the body.
Causes of fibula damage
The most common significant medical conditions of the fibula are fractures. The possible causes of fractures are
- The main type of fracture occurs at the distal end of the bone and is classified as an ankle fracture. Trauma to the fibula can be caused by a single episode of significant twisting force or repetitive high-impact exercise forces.
- Repetitive high-impact exercises, such as running and jumping, can lead to stress fractures in the upper third part of the fibula.
- External twisting motions of the ankle can lead to spiral fractures of the distal (far) end of the fibula.
- Malignant tumors in the fibula are rare, but life-threatening. The proximal fibula is the common area to be affected by tumors which include osteosarcoma, giant cell tumors, chondrosarcoma and aneurysmal bone cysts.
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