Your shinbone is named after a Roman flute
The tibia takes its name from the flute of the same name. It is the second-largest bone in the body after the femur and carries almost all the weight passing from knee to ankle, while the slimmer fibula beside it barely moves. Its sharp front edge is why a knock on the shin hurts so much.
Sitting on the inner side of the lower leg, the tibia is the bigger and stronger of its two bones and the one in front. A tough sheet called the interosseous membrane ties it to the fibula in a fibrous joint that permits very little movement. As a long bone it has a shaft and two rounded ends, and it forms from three centres of bone growth, one in the shaft and one at each end. It narrows most in its lower third.
The top is broad and flattened into two condyles, the inner one larger and better supported. Together with the ridge between them they form the tibial plateau, where the femur rests and the knee's weight-bearing joint is made. The cruciate ligaments and the cartilage pads called menisci anchor in the area between the condyles. Just below lies the tibial tuberosity, a bump that receives the patellar ligament, the continuation of the big quadriceps muscle of the thigh.
The shaft is triangular in cross-section with three borders. The front one, the anterior crest, runs from the tuberosity down to the ankle and is sinuous and prominent for most of its length; much of the adjoining inner surface lies directly under the skin with no muscle cushion. At the bottom the bone shrinks and sends down a strong pyramid-shaped process, the medial malleolus, the knob on the inside of the ankle. With the fibula and the talus it forms the ankle joint.
In all, the tibia takes part in four joints: the knee, the ankle and upper and lower connections with the fibula. A nutrient artery provides most of its blood. Its toughness has limits under odd conditions: in a pilot study, rats kept with hind limbs unloaded to mimic weightlessness and given one gray of radiation had tibias 37 percent weaker in bending tests, while their femurs were unaffected.
Source: Tibia
