The tibia is the shin bone: the thick bone at the front of the lower leg that carries your weight. The fibula is the slimmer bone alongside it on the outer side, which bears little weight and mainly provides muscle attachment and ankle stability.
The core difference
Two bones in the lower leg, sharply different in size and role.
- tibia — the shin bone; the second-largest bone in the body; carries almost all the load.
- fibula — the slender outer bone; minimal weight-bearing; stabilises the ankle.
A way to remember it
The tibia is the one you can feel as a hard ridge down the front of your shin. The fibula runs down the outside and is harder to feel except at the ankle, where its lower end forms the bony bump on the outer side.
The words
Tibia is Latin for a flute or pipe — the bone was used to make them. Fibula is Latin for a brooch or clasp, apparently because the two bones together resemble a pin-and-clasp fastening.
This page explains the words. It is not medical guidance.
Frequently asked questions
Which bone is the shin?
The tibia — the thick weight-bearing bone at the front of the lower leg.
What does the fibula do?
It provides muscle attachment and stabilises the ankle, bearing very little body weight.
Why is it called a tibia?
Latin for flute or pipe — the bone was historically used to make them.