Is a knee joint bone or tendon?

The knee joint is not a bone or a tendon. It is a synovial joint, which is a type of joint that allows for movement between two bones. The knee joint is composed of the femur (thigh bone), the tibia (shin bone), and the patella (kneecap). The bones are connected by ligaments, which are bands of tough, flexible tissue that help to stabilize the joint. The joint is also lined with a synovial membrane, which produces a lubricating fluid that helps to reduce friction between the bones.