There are more than 200 bones in the human body. Some of these, like those in the skull and the ribcage, serve to protect other structures and organs. Others work to help with balance, such as the bones of the toes. Still others work to support, such as the main bone of the leg, the tibia. A bone that is closely related to the tibia is the fibula. The fibula has its own role in the body.
The fibula, also known as the calf bone, is one of the two main bones of the lower leg. It is thinner than the other bone of the lower leg, the tibula, and it is the outer of the two bones. The fibula is connected to the upper tibia only by ligaments and is not truly connected to the knee, but it is joined to the talus (ankle bone). This joint is the section of bone that protrudes from the outer side of the ankle.
The fibula is significantly thinner than its partner bone, the tibia. As a result, it is not designed to carry much weight, although it does support a bit. The fibula’s main function, therefore, is to act as a stabilizing bone, particularly for the ankle.
One interesting fact about the fibula is that its function and strength is not the same from mammal to mammal. For instance, mammals that spend less time on the ground (e.g., chimpanzees) have fibulas that are stronger than the fibulas found in mammals that are more terrestrial. Additionally, in some species, the fibula actually is fused to the tibia for a length, which gives it more strength.
Injuries to the fibula are not that uncommon, but because the fibula acts like a stabilizer rather than a weight-bearing bone, it’s much more likely that a person will injure the fibula as a result of an injury to the tibia. For instance, if the tibia is fractured, more weight is placed on the fibula, and the fibula thus may fracture, as well, since the fibula is not designed to carry very much.
Because bone is live tissue, it is subject to the same transplant restrictions as other organs of the body. Doctors, therefore, experience some degree of limitation when looking for bone that can be used in reconstruction surgeries and other procedures. The fibula, however, provides doctors with viable medical options—doctors can remove up to 26 centimeters of fibula tissue without creating problems with fibula function.