The slender bone on the outer side of the lower leg, which carries almost none of the body's weight
Fibula — the calf bone, for muscle attachment.
Anatomy · Bones
Fibula
The slender bone of the lateral leg
Lower limb · leg
The fibula is the slender bone on the outer (lateral) side of the leg, running parallel to the tibia. It bears little of the body's weight and serves mainly for muscle attachment, but its lower end forms the lateral malleolus, the outer bump of the ankle, which stabilises the ankle joint. Its Latin name means a brooch or pin.
How to spot them
- ▸Long, very slender rod lateral to the tibia, largely hidden beneath muscle
- ▸Small knob-like head at the top, which meets the underside of the tibia's lateral condyle but does not reach the knee joint
- ▸Lower end enlarged into the lateral malleolus, the outer ankle bump, which extends lower than the inner one
- ▸Only the head and lateral malleolus can be felt under the skin
What to know
Its Latin name means a brooch or clasp
Fibula — Latin fibula, a pin or brooch; the bone is thin like the pin of a brooch.
Its lower end forms the outer bump of the ankle, projecting further down than the inner one
Fibula — the lateral malleolus.
A nerve winds around its neck just below the knee, and its compression there can cause foot drop
Fibula — the common fibular (peroneal) nerve.
Surgeons may harvest a length of it, with its blood vessels, to rebuild a jaw, and the leg still functions
Fibula — the free fibular flap.
It does not reach the knee joint: its knob-like head meets only the underside of the outer condyle of the shin bone
Fibula — the proximal tibiofibular joint.
A spiral fracture of its upper third, with an ankle injury that tears the ligaments joining it to its neighbour, is named after a French surgeon, Maisonneuve
Fibula — the Maisonneuve fracture (proximal fibula fracture with syndesmosis and deltoid ligament injury or medial malleolus fracture).
Key ideas
- It carries only a small fraction of the load (figures of well under a fifth are quoted); its role is as a site for muscle attachment and as the lateral wall of the ankle mortise.
- Because it does not bear much weight, a section of the shaft can be removed without disabling the leg, which is why surgeons use it as a bone graft.
Quick-fire facts
- •It is the lateral bone of the leg, thinner than the tibia and not weight-bearing.
- •The head of the fibula articulates with the lateral condyle of the tibia at the proximal tibiofibular joint; the lower end articulates with the tibia and the talus.
- •The common fibular nerve winds around the neck of the fibula, and is vulnerable to injury there.
- •The lateral malleolus is longer and extends lower than the medial malleolus.
- •Only the ends of the fibula can be palpated; the shaft is surrounded by muscles.
- •It is commonly used as a bone graft donor, for example the free fibula flap for jaw reconstruction.
- •The interosseous membrane joins the fibula and tibia.
- •Fibula is Latin for a brooch or pin, the kind of clasp the Romans used to fasten a cloak.
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Sources
- OpenStax — Anatomy and Physiology 2e — 8.4 Bones of the Lower Limb
- TeachMeAnatomy — Bones of the Lower Limb