The thin bone of the calf

Fibula · fibula

The slender bone running alongside the shin, mainly there to steady the ankle and anchor muscles.

What it does

The fibula runs parallel to the tibia on the outside of your lower leg. It carries only a small share of your weight. Its main jobs are to give muscles somewhere to attach and to form the bump on the outside of your ankle, which keeps the ankle joint stable.

Surprising fact

Because the fibula carries so little weight, surgeons can remove a section of it and use the bone to rebuild a damaged jaw.

Why it matters

When you roll your ankle, the outer bump of the fibula is often the part that breaks. Feeling for that bump is also a quick way to find where the outer ankle ligaments sit.

Nearby

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Sources

Drafted with AI help; awaiting a human fact-check against these sources.

Open in the 3D atlas · Suggest a correction · Not medical advice.

3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.