térdízületet

The térdízület, or knee joint in English, is a complex and vital hinge joint in the human leg. It is the largest joint in the body and plays a crucial role in locomotion, allowing for flexion and extension of the lower leg relative to the thigh. The knee joint is formed by the articulation of three bones: the femur (thigh bone), the tibia (shin bone), and the patella (kneecap). The patella acts as a shield for the front of the joint and improves the leverage of the quadriceps muscles.

The joint is surrounded by a capsule and is further stabilized by a network of ligaments. The cruciate ligaments, the anterior and posterior cruciate ligaments, are located within the joint and prevent excessive forward and backward movement of the tibia. The collateral ligaments, the medial and lateral collateral ligaments, are on the sides of the knee and limit sideways motion. Menisci, C-shaped pieces of cartilage located between the femur and tibia, act as shock absorbers and help to distribute weight across the joint surface, improving stability and congruence.

The articular surfaces of the bones are covered with hyaline cartilage, which reduces friction and allows for smooth movement. The joint is lubricated by synovial fluid, produced by the synovial membrane lining the joint capsule. This fluid nourishes the cartilage and further reduces friction. The muscles surrounding the knee, primarily the quadriceps femoris on the front and the hamstrings on the back, provide the dynamic force for movement and contribute to joint stability. Injuries to the térdízület are common and can affect ligaments, menisci, cartilage, or bone.