The tibia, shinbone or shank bone, is the larger and stronger of the two bones in the leg below the knee in vertebrates (the other being the fibula), and connects the knee with the ankle bones. The tibia is named for the Greek aulos flute, also known as a tibia. It is commonly recognized as the strongest weight bearing bone of the body. In human anatomy the tibia is the second largest bone next to the femur. As in other vertebrates the tibia is one of two bones in the lower leg, the other being the fibula, and is a component of the knee and ankle joint. The tibia derives its arterial blood supply from two sources: A nutrient artery, as the main source, and periosteal vessels derived from the anterior tibial artery. The ossification or formation of the bone starts from three centers; one in the shaft and one in each extremity.