The fibulabone is the smaller of the two long bones in the lower leg, running parallel to the shinbone (tibia). It sits on the outside of the leg, from just below the knee to the outer side of the ankle. Unlike the tibia, it does not bear significant body weight, but it plays a vital role in ankle stability and muscle attachment.
Where Is the Fibula Located?
The fibula runs from the knee down to the ankle on the outer edge of your lower leg. It is a long, thin bone with a distinct head at the top and a prominent bump at the bottom called the lateral malleolus.
That bump on the outside of your ankle is part of the fibula. You can feel it easily. The top end connects to the tibia just below the knee joint, but it does not actually form part of the knee joint itself. The bottom end forms the outer part of the ankle joint.
What Does the Fibula Do?
The fibula has several important jobs, even though it does not carry your body weight. The tibia handles nearly all of the weight-bearing load in the lower leg.
First, the fibula provides structure and stability to the ankle joint. The lateral malleolus acts like a wall that keeps the ankle bones from sliding sideways. Without it, the ankle would be highly unstable.
Second, many muscles in the lower leg attach to the fibula. These muscles control movement of the foot and toes. The fibula gives these muscles a solid anchor point to pull against.
Third, the fibula helps distribute forces that travel up the leg during walking and running. Some research suggests it carries roughly 6-10% of the load during normal walking, though the exact percentage varies.
Fibula vs. Tibia: What Is the Difference?
The tibia and fibula are often confused because they sit side by side. They are very different bones with different roles.
The tibia is the larger, stronger bone. It is the main weight-bearing bone of the lower leg. The fibula is thinner and sits on the outside. It is not designed to support body weight.
| Feature | Tibia | Fibula |
|---|---|---|
| Size | Larger and thicker | Smaller and thinner |
| Location | Inner side of lower leg | Outer side of lower leg |
| Weight-bearing | Bears most of body weight | Bears minimal weight |
| Ankle role | Forms inner ankle bump | Forms outer ankle bump |
| Knee role | Forms lower part of knee joint | Does not form part of knee joint |
Both bones connect at the top and bottom, with a membrane running between them. This structure keeps them working together as a unit.
What Is The Fibulabone’s Role in the Ankle?
The fibula is essential for a stable ankle. The bottom end of the fibula forms the lateral malleolus, which is the hard bump on the outside of your ankle.
This bump fits into the side of the ankle joint and prevents the foot from sliding too far sideways. When you twist your ankle, the ligaments that connect the fibula to the foot are often what get stretched or torn. This is why ankle sprains commonly involve pain on the outer side of the ankle.
The fibula also moves slightly during ankle motion. It rotates and shifts to accommodate the changing shape of the ankle joint as you point and flex your foot. This movement is small but important for smooth, pain-free motion.
What Injuries Can Affect the Fibula?
Several types of injuries can involve the fibula. The most common is an ankle sprain, which damages the ligaments attached to the fibula rather than the bone itself.
Fractures of the fibula can occur at different points along the bone. A fracture near the ankle is often called a lateral malleolus fracture. These range from small hairline cracks to complete breaks that require surgery. A fracture near the knee is called a fibular head fracture.
Stress fractures can also develop in the fibula, especially in runners who suddenly increase their mileage. These are small cracks that develop from repetitive force over time. They cause a dull ache that worsens with activity and improves with rest.
In some cases, the fibula can be injured along with the tibia. This happens in high-energy accidents like car crashes or severe falls. These injuries are more serious and often require surgical repair.
How Are Fibula Fractures Treated?
Treatment depends on the location and severity of the fracture. Many fibula fractures can be treated without surgery.
Stable fractures where the bone pieces remain aligned are typically treated with a cast or walking boot. The bone usually heals within 6-8 weeks. During this time, weight-bearing is gradually introduced as the bone strengthens.
Unstable fractures, or fractures that affect the ankle joint alignment, usually require surgery. Metal plates and screws are used to hold the bone fragments in the correct position. Surgery is needed when the ankle joint would otherwise become misaligned, which could lead to long-term arthritis.
Recovery from fibula surgery typically takes longer than non-surgical treatment. Physical therapy is essential to regain strength and range of motion in the ankle and leg.
What Happens If the Fibula Is Removed?
In rare cases, a portion of the fibula may be removed surgically. This happens most often when a bone tumor is present or when the fibula is used as a bone graft for another part of the body.
The fibula can be partially removed without causing major disability. The tibia is able to compensate for the missing bone in most cases. However, ankle stability may be affected, especially if the lower portion of the fibula is removed.
Some surgeons recommend fusing the remaining fibula to the tibia if a large portion is removed. This helps maintain ankle stability. Patients who have partial fibula removal often do well but may have some limitations with high-impact activities.
How Do You Keep the Fibula Healthy?
Keeping your fibula healthy is mostly about keeping your bones and ankles strong. The same habits that protect all your bones also protect the fibula.
Weight-bearing exercise like walking, running, and strength training helps maintain bone density. Strong leg muscles also protect the fibula by absorbing forces that would otherwise stress the bone.
Ankle strengthening exercises can reduce the risk of ankle sprains, which are the most common fibula-related injury. Balance exercises and calf raises are simple ways to improve ankle stability.
Adequate calcium and vitamin D intake supports bone health at every age. These nutrients are essential for bone repair and maintenance. Most adults need about 1000 mg of calcium and 600-800 IU of vitamin D daily, though individual needs vary.
Frequently Asked Questions
Can you walk with a fractured fibula?
Some people can walk on a fractured fibula, but it is usually painful and not recommended. You should see a doctor for an evaluation before putting weight on a potentially broken leg.
How long does a fibula fracture take to heal?
Most fibula fractures heal in 6-8 weeks with proper treatment. More severe fractures or those requiring surgery may take 3-4 months to fully heal.
Is the fibula a weight-bearing bone?
The fibula carries only a small percentage of body weight, around 6-10% during walking. The tibia carries the majority of the load.
Why does the outside of my ankle hurt?
Pain on the outside of the ankle often involves the fibula or its attached ligaments. Ankle sprains are the most common cause, but fractures and tendon problems can also cause this pain.
