The tibia is a large bone located in the lower front portion of the leg. The tibia is also known as the shinbone, and is the second largest bone in the body. There are two bones in the shin area: the tibia and fibula, or calf bone. The fibula is smaller and thinner than the tibia. These two bones connect the ankle to the knee and work together to stabilize the ankle and provide support to the muscles of the lower leg; however, the tibia carries a significant portion of the body weight.