The term Fibula Neighbors refers to the two bones in the lower leg, the fibula and the tibia. The tibia, which is the larger of the two bones, is sometimes referred to as the shinbone or shankbone. It is the second largest bone in the body and runs from the knee to the ankle. The fibula is the smaller of the two bones and runs parallel to the tibia. Together, the fibula and tibia form the lower leg and provide support for the muscles and ligaments of the leg.