The fibula connects to the tibia at the ankle and provides for stability in movement. Below the knee it connects to the other leg bone the tibia that allows for articulation between the two bones in the tibiofibular joint it forms. The fibula is not a structural bone and is positioned on the outer edge of the leg. It is the most slender of the long bones.
At the upper extremity it is small and is placed toward the back of the tibia. The superior tibiofibular articulation is below the kneecap and not part of that joint. This is an arthrodial joint between the lateral condyle of the tibia and the head of the fibula. The inferior tibiofibular articulation (where the fibula joins at the ankle and articulates with the tibia) is formed by the rough, convex surface of the medial side of the lower end of the fibula, and a rough concave surface on the lateral side of the tibia.