Joints, particularly hinge joints like the elbow and the knee, are complex structures made up of bone, muscles, synovium, cartilage, and ligaments that are designed to bear weight and move the body through space. The knee consists of the femur (thigh bone) above, and the tibia (shin bone) and fibula below. The kneecap (patella) glides through a shallow groove on the front part of the lower thigh bone. Ligaments and tendons connect the three bones of the knee, which are contained in the joint capsule (synovium) and are cushioned by cartilage.
Review Date 11/23/2021
Updated by: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.