Fibula has the following functions: 1. It can play the role of supporting the tibia, many patients think that the fibula is the same as the tibia, which is the weight-bearing part. But in fact, in the calf, the tibia is the main weight-bearing part, and the fibula is not involved in weight-bearing, only to play a secondary role in supporting the tibia. 2, the fibula has a lot of muscle tendon attachment, this part has a series of muscle, tendon starting and ending points, so the fibula can provide support for it, such as the lateral calf muscles, basically from the fibula. 3, it can protect the important internal structures, in the fibula of the inner side of the important blood vessels, nerves, the fibula can provide support. There are important blood vessels and nerves on the inner side of the fibula, which can be protected by the fibula.4. The fibula is involved in the formation of the ankle, the so-called outer ankle refers to the outer side of the ankle joint, where there is a very obvious bony protrusion, which can be seen in the part of the fibular tuberosity. The tip of the fibula and the talus below it form the joint of the ankle, so the fibula is involved in the formation of the ankle joint.