  The fibula is commonly known as the calf bone. It's the weight-bearing bone that extends to the ankle from the knee. It runs parallel to the tibia, which does is not w … eight-bearing.he fibula is connected by a synovial joint to your other shin bone, the tibia. The … fibula is what makes your outer ankle bone. And the tibia makes your inner 'ankle' bone. The main job of the tibia is to form a hinge joint with the femur, which allows you to walk, run, kick a ball, and generally have fun.