The fibula is one of the two bones of the lower leg. This belongs to the long bones.
What is the fibula?
The fibula is a tubular lower leg bone. Together with the tibia (shin bone), to which it attaches on the outside, it forms the human lower leg. The fibula is thinner in circumference than the tibia. The term fibula comes from Latin. Translated into German, it means something like “brace” or “staple”. The fibula is firmly attached to the tibia and provides the articular surface for the upper ankle joint. Fibers provide the connection between the fibula and the tibia. The fibula is located on the outer side of the lower leg. Painful injuries such as a fibula fracture can occur at the fibula.
Anatomy and structure
The fibula is composed of the fibular shaft (corpus fibulae), the fibular neck (collum fibulae), the fibular head (caput fibulae), and the lateral malleolus (malleolus lateralis). The shaft of the fibula has three sharp edges. These are called the margo anterior, margo interosseus, and margo posterior. Between them are three surfaces called facies posterior, facies lateralis, and facies medialis. The multiple division is caused by the large number of muscle origins. In the intermediate area of the margo interosseus as well as the edge of the tibia, which bears the same name, runs the membrana interossea cruris. The tight connective tissue membrane divides the human lower leg into an anterior as well as a posterior region. On the back of the fibula, the crista medialis separates the original surface of the posterior tibialis muscle and the surface of the flexor hallucis longus muscle. The fibula neck serves as a link between the fibular shaft and the fibular head. Another important component of the fibula is the fibular head. On the outer side, the fibular head can be felt just below the knee. However, it has no part in the formation of the knee joint. The connection to the tibia is established by a cartilaginous articular surface. This is called the facies articularis capitis fibulae. There is a connection between it and the facies articularis fibularis at the condyle lateralis of the tibia. In the proximal direction is the prominent tip of the fibula, which is called the apex capitis fibulae. At the lower end of the fibula is the external malleolus, which is formed by a strong distension. It is closely adjacent to the tibia and has its own articular surface. This is the facies articularis malleolaris lateralis. The lateral malleolus extends further in the distal direction than the tibia. Together with the medial tibial malleolus, it forms the malleolar fork (ankle fork). This grasps the ankle bone (talus) between them.
Function and tasks
Development of the fibula begins as early as the 2nd embryonic month. During this process, a perichondral bone cuff develops in the corpus. During the 2nd year of life, formation of an enchondral bone nucleus occurs within the ankle, which does not occur in the fibula until four years of age. Between the ages of 16 and 19, distal closure of the epiphyses begins. Between 17 and 20 years of age, closure toward the middle of the body also occurs. While the course of the proximal epiphyseal line is under the fibular head, the distal line is over the malleolus. The lower section of the fibula is important for the upper ankle joint. Thus, from this point, forces acting on the leg are transmitted between the bones toward the tibia and femur via the articulatio tibiofibularis proximalis (tibiofibular joint). In contrast, the fibula exerts no functional influence on the knee. Thus, it has only indirect involvement through the fibular head.
Diseases
The fibula in humans can be affected by various injuries. First and foremost among these is the fibula fracture. This fracture occurs mostly as a result of accidents in which the fibula is damaged to a significant degree. The fracture is often extremely painful and healing requires some patience from the patient.It is not uncommon for a fracture of the fibula to be caused by direct exposure to force such as a kick during a soccer match. In addition, fibula fracture is also frequently associated with knee injuries. In addition, bone diseases such as osteoporosis (bone loss) or tumors are sometimes responsible for fracture of the fibula. Typical symptoms of a fracture include severe pain, bruising, and the formation of a swelling. In most patients, treatment of a fibula fracture consists of surgical intervention in the form of osteosynthesis. This involves the placement of set screws or plates made of metal. Likewise, intramedullary nailing is within the realm of possibility. A variant of the fibula fracture is the fibula shaft fracture. A fracture of the fibular head is also possible. This usually occurs as a result of direct impact of the head, which in turn usually occurs during soccer. In addition, this type of fracture can affect the peroneal nerve (lower leg nerve). Another injury that occurs rather rarely, however, is the syndesmosis rupture. This involves a rupture of the tight fibrous connection that exists in the ankle region between the fibula and tibia. After such an injury, surgical immobilization is not infrequently required in order for the affected person’s ankle joint to regain its stability. Fibulaplasia is one of the diseases of the fibula. In this condition, the fibula does not form properly.
Typical and common bone diseases
- Osteoporosis
- Bone pain
- Bone fracture
- Paget’s disease
