The knee is the largest and one of the most complex joints in the human body. It consists of 4 bones, multiple ligaments, muscles and tendons, cartilage and soft tissue. The boney structures of the knee consist of the patella (knee cap), Femur (thigh bone), Tibia and Fibula (lower leg bones). The smoothness motion of the knee is accomplished through articular cartilage and fibrocartilage. Articular cartilage is the protective covering over the ends of the bones. Meniscus is the additional form of cartilage within the knee called fibrocartilage. The purpose of your two meniscuses (medial – inside and lateral – outside) is to act as cushions between your femur (thigh bone) and tibia (lower leg bone). Both kinds of cartilage allow the joint to glide permitting fluid motion during active and passive activities. The breakdown of either one of these cartilaginous structures can advance arthritic changes.