The knee is a complex joint that connects the femur (thigh bone) to the tibia (shin bone). It is made up of several key components, including the patella (kneecap), ligaments, tendons, and cartilage. The knee joint allows for bending and straightening, enabling activities like walking, running, and jumping. Ligaments, such as the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), provide stability, while the menisci are C-shaped cartilage that cushion the joint. The knee is surrounded by synovial fluid, which lubricates the joint and reduces friction during movement.