What is the function of the fibular bone

Structure and function of the knee and lower leg


The Knee joint is mainly a flexor and extensor joint, rotations are only possible to a limited extent - one speaks of a [swivel] hinge joint. The bony parts of the joint form this Shin (Tibia) and the thigh bone (femur) with its two cylindrical elevations (joint rollers), the Condyles. These lead a combined rolling and sliding movement on the almost flat joint surface of the tibial head, the Tibial plateau (Shin plateau). On the two outer sides of the tibial plateau there are two crescent-shaped cartilaginous structures, the Menisci. They improve the contact between the rounded condyles and the flat plateau and at the same time ensure effective absorption of hard impacts thanks to their elasticity. The joint is held together by a complex capsule-ligament device. Two ligaments that run directly in the joint are particularly important for stabilization Cruciate ligaments. Starting from an elevation in the middle of the tibial plateau, they run, crossing one another, in the groove between the two condyles. The cruciate ligaments ensure constant close contact between the thighbone and the shinbone and prevent the condyles from sliding forwards or backwards. On both sides the knee is supported by the inner and outer sideband stabilized. These reinforcement cords of the joint capsule protect against lateral buckling of the joint. In addition, many muscles cross the knee joint with their tendons and also stabilize it. The strongest tendon is that of the four-headed thigh muscle (quadriceps muscle), which pulls on the front of the knee to the head of the tibia and into the - as the largest sesamoid bone (below) of the body - bony Kneecap (Patella) is incorporated. The tendon portion above the kneecap is called Quadriceps tendon, the one below Patellar tendon (Ligamentum patellae).

As Sesame bone (Os sesamoideum) is the name of a small bone that has grown into a tendon and provides additional distance to the bone. This minimizes pressure loads that tendons are exposed to as they travel across joints.

Although in Knee area four bones meet, only the thighbone and the shinbone are directly involved in the formation of the joint. With its two cartilaginous joint rollers, the condyles, the lower end of the thigh bone slides on the flat joint surface of the head of the tibia, the tibial plateau. At the front of the knee is the kneecap. At its upper pole it is connected to the thigh muscles by a tendon, at its lower pole by a strong ligament with a protruding bone from the head of the tibia (tibial tuberosity). Below the knee joint lies the head of the fibula.
Georg Thieme Verlag, Stuttgart

Lower leg

In contrast to the thigh, the lower leg consists of two bones: the shin and the Fibula (Fibula). While the tibia, which is easily palpable on the front of the lower leg, measures 5 cm in diameter and therefore bears the main burden of the body weight, the fibula, 1 cm in diameter, is relatively thin and not directly involved in the knee joint. Between the two bones there is a solid layer of fibers, the interosseous membrane. The tibia and fibula together form the upper part of the ankle.

The knee is stretched by the thigh muscles and the thigh and lower leg muscles are flexed. The muscles of the lower leg are also responsible for the flexion and extension of the ankle joint, and sometimes also for the lifting and lowering of the toes. The largest muscle of the lower leg is the gastrocnemius muscle at the back of the calf, commonly called the Calf muscle known.


Dr. med. Martin Schäfer, Dr. med. Poor Schäffler in: Gesundheit heute, edited by Dr. med. Arne Schäffler. Trias, Stuttgart, 3rd edition (2014). Revision and update: Dr. med. Sonja Kempinski | last changed on at 15:45