Tibia and fibula are two parallel bones that form the skeleton of leg by connecting the knee and ankle. Both bones articulate with each other proximally and distally with the aid of strong interoseus membrane, which helps to transfer the forces between them. Tibia and fibula are nearly equal in length, and play major roles in the structure and stability of the ankle joint, yet only tibia participates to form the knee joint.
Tibia
Tibia is a large and strong bone that connects ankle and knee by articulating with femur in the proximal region, forming a hinge joint, and by articulating with talus bone in the ankle at its distal end. Tibia is also known as shinbone, and it is the second largest and strongest bone in the body. The main role of the tibia is to transfer the bodyweight from femur to foot. The proximal end of tibia is broad and contains two concave condyles; lateral condyle and medial condyle that articulate with lateral and medial condyles of the femur at knee joint. Tibial tuberosity, the prominent process on the anterior surface, provides the point of attachment for the patellar ligament. Anterior crest of the tibia does not have a muscle cover. At the distal end of tibia, the medial surface forms medial malleolus, which articulates with talus bone of the ankle. The point of articulation with the fibula is the fibular notch.
Fibula
Fibula is a long sticklike bone, which is connected to tibia at both distal and proximal ends laterally. It does not serve to transfer the bodyweight, but provides sites for muscle attachments. An enlarged head is found at its proximal end where the lateral condyle of tibia articulates. At its distal end, a projection called lateral malleolus articulates with the talus. Lateral malleolus is responsible for providing stability to the ankle and its bones. Fibula is bound to the tibia at its medial border by an interoseus membrane.
What is the difference between Tibia and Fibula?
• Tibia is larger and stronger than fibula.
• Fibula does not form the knee joint, whereas tibia does.
• Tibia is a weight bearing bone, whereas fibula is non-weight bearing bone.
• Proximal end of tibia articulates with femur, while that of fibula articulates with the tibia.
• The thickness of the tibia is much greater than the fibula.