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Anatomy of Tibia and Fibula

There are 2 bones in the lower leg, tibia and fibula.

Fibula is an elongated bone located on the external side of the lower leg.

The function of the fibula is transferring the weight from the shin to the foot.

Tibia: The tibia known as the shin bone, is the larger

and stronger of the two lower leg bones.

The tibia is located in the lower leg medial to the fibula, distal to the femur and proximal

to the talus of the foot.

The proximal end is roughly flat with the smooth, concave medial and lateral condyles

forming the knee joint with the femur.

At the inferior edge of the lateral condyle is a small facet where the tibia forms the

proximal tibia fibular joint with the fibula.

This joint is a planar joint, allowing the tibia and fibula to slightly glide past each

other and adjust the position of the lower leg.

Fibula:

The fibula is the long, thin and lateral bone of the lower leg.

It runs parallel to the tibia, or shin bone, and plays a significant role in stabilizing

the ankle and supporting the muscles of the lower leg.

Compared to the tibia, the fibula is about the same length, but is considerably thinner.

The difference in thickness corresponds to the varying roles of the two bones; the tibia

bears the body's weight from the knees to the ankles, while the fibula merely functions

as a support for the tibia.

At the fibula's proximal end, just below the knee, is a slightly rounded enlargement known

as the head of the fibula.

The head of the fibula forms the proximal (superior) tibiofibular joint with the lateral

edge of the tibia.

From the proximal tibiofibular joint, the fibula extends slightly medially and anteriorly

in a straight line toward the ankle.

Upon reaching the ankle, the fibula swells into a bony knob known as the lateral malleolus,

which can be seen and felt protruding from the outside of the ankle joint.

At the medial malleolus, the fibula forms the distal (inferior) tibiofibular joint with

the tibia and also the talocrural (ankle) joint with the tibia and talus of the foot.