12/01/2026
The human knee is the body's largest and one of its most critical joints for mobility and weight-bearing, allowing essential movements like walking, running, and jumping. It connects the thigh bone to the lower leg bones and is a complex structure of bones, cartilage, ligaments, and muscles that work in unison.
Key Functions of the Human Knee
The importance of the knee is reflected in its diverse roles in daily life:
Movement: The knee primarily functions as a modified hinge joint, allowing the leg to bend (flexion) and straighten (extension). This range of motion is crucial for almost any activity involving the legs, including sitting down and standing up, climbing stairs, cycling, and swimming.
Weight-Bearing: The knee is a primary weight-bearing joint, supporting the body's weight during both static positions (standing) and dynamic activities (running, jumping). The forces on the knee can be several times the body's weight during high-impact activities.
Shock Absorption: The menisci (crescent-shaped cartilage discs) and articular cartilage in the knee act as essential shock absorbers, cushioning the impact between the femur and tibia and protecting the bones from damage.
Stability and Balance: Ligaments (such as the ACL, PCL, MCL, and LCL) provide crucial stability by connecting bones and preventing excessive side-to-side or front-to-back movements. Muscles surrounding the joint, like the quadriceps and hamstrings, also offer dynamic stabilization and help maintain balance.
Force Transmission and Leverage: The patella (kneecap) acts as a fulcrum, increasing the leverage and efficiency of the quadriceps muscles, which improves force transfer and allows for powerful movements like extending the leg.