Fibula: What to Know

Medically Reviewed by Poonam Sachdev on September 01, 2022
5 min read

Known for providing stability to your lower leg and giving your calf its structure, the fibula is the longest, thinnest bone in the lower leg and plays a significant role in supporting important tendons, nerves, muscles, and ligaments.

Whenever you stand or move around, your tibia (the other bone in your lower leg) supports your body weight. The tibia also forms parts of your knee and lower ankles. The fibula’s main function is to serve as support for the tibia.

Your fibula meets the tibia just below the knee. The end of your fibula (also known as its head) moves with the tibia whenever you move your knee joint. 

Shaped like a three-sided prism, the shaft is the longest portion of your fibula and is responsible for making up your calf's structure. Forming the top of your ankle joint, meanwhile, is the fibula distal aspect, which is connected to your anklebone and your tibia. 

Some of the important jobs your fibula has include:

  •  Providing support for your ankles 
  •  Providing support for the muscles and tendons in your legs and ankles
  •  Forming the structure of your lower leg and calf
  • Connecting upper leg bones and knee ligaments to lower leg bones 

The femur and tibia are stronger and thicker than the fibula, which is why it's more common to break the latter or experience a fracture. When you fracture your fibula, in some cases, you may require surgery and physical therapy to experience a full recovery. As you age, osteoporosis can put your bones at risk of becoming weak, and repetitive stress exercises like lifting weights can cause your fibula to sustain a stress fracture. 

The fibula is the smaller of the two bones in your lower leg. It starts just under the knee and runs through your ankle. It runs parallel to the tibia and can be found closest to the outside of your body. Running from just under your knee to your ankle, the fibula is the smaller of the two bones in the lower leg.

The most common issues that lead to fractures or issues with the fibula are osteoporosis and simple fall accidents.

Osteoporosis is a condition that many individuals don't even realize they're living with until they break a bone. Individuals most at risk for osteoporosis include women and adults over the age of 50. Bone fractures are the most common resulting issues and can be caused by repetitive, high-impact exercises, simple falls, sports injuries, motor vehicle accidents, or any other injury involving significant force to the area.

The kind of bone injury you have will determine the type of fibular fracture you experience. Some of the most common include: 

  • Lateral malleolus fractures (occur at the ankle)
  • Avulsion fractures (occur when the ligament or tendon pulls a part of the bone it's attached to)
  • Fibular head fractures (occur at the knee portion of fibula bone)
  • Fibular shaft fractures (occur in the middle of the fibula bone)

Pain, swelling, and tenderness around the area are some of the most common symptoms of a fibula fracture. Other signs of a fractured fibula include:

  • Bruising or bleeding in the leg 
  • Numbness or tingling in the feet
  • When putting pressure on your leg, pain increases 
  • Being unable to bear weight on a leg may be a sign of a fibula fracture 
  • A noticeable deformity or bump on the lower leg
  • Being unable to move your legs as you normally would 

Seeking medical care as soon as possible if you believe you've sustained leg trauma or experienced a fracture is important. During a physical exam, your doctor will begin by looking for noticeable changes in your lower leg. Next, they might use an x-ray to see if there is a fracture and whether the bone has been displaced. An MRI can provide a more detailed scan; your doctor may recommend this to better understand what the interior bones and soft tissue look like. Making a proper diagnosis and appropriately judging the severity of the injury may require your doctor to conduct several tests, including these bone scans. 

Unless you've suffered a fracture or were diagnosed with osteoporosis, you won't typically require extensive treatment for your fibula. If you've fractured your fibula, what caused it and the type of fracture you sustain will determine your course of treatment. 

Stress fractures, for instance, are typically treated without surgery and often heal on their own. Rest and avoiding weight bearing generally are generally recommended treatments for these types of fractures. 

While there are often no complications with fractured fibulas, in some cases, an individual may experience further problems like long-term pain, chronic swelling, or permanent damage to blood vessels around the ankle joint. Meanwhile, exercise and adding vitamins to your regular routine are usually recommended as treatment options for osteoporosis, alongside certain medications. 

When you injure your fibula, beginning treatment as soon as possible is one of the best things you can do to ensure you fully recover. Apply ice to the injured area and keep your leg elevated right after the accident. In most cases of fibular fracture, crutches, a walking boot, or a brace may be recommended to immobilize your lower leg. Physical therapy, stretching, and regular exercises to strengthen the area are recommended whether you've undergone surgery for your injury or can make a quick and complete recovery at home. 

Getting medical attention as soon as possible after an injury is the best way to get back on track for a full recovery and ensure that you won't injure the bone further. Water exercises like swimming are great for rehabilitating a weak fibula after sustaining a fracture. 

As it repairs the injury, your body needs time to heal, which could take as long as six weeks. Rushing the process by going against your doctor's advice may simply risk reinjuring yourself and prolonging your recovery. 

In the meantime, following safety tips like wearing your seatbelt protective gear during sports and a regular exercise plan can decrease your risk of falls or accidents resulting in a fibula fracture.