Osteoarthritis, also known as degenerative joint disease, is the most common form of arthritis. In this disorder, a joint loses cartilage, the slippery material that cushions the ends of bones, over time.
As a result, the bone beneath the cartilage changes and develops bony overgrowth. The tissue that lines the joint can become inflamed, the ligaments can loosen, and the muscles around the joint can weaken. The patient feels pain and movement limitations when using the joint.
|Click the icon to see an animation about osteoarthritis.|
Joints provide flexibility, support, stability, and protection. Specific parts of the joint, the synovium and cartilage, provide these functions.
Synovium. The synovium is the tissue that lines a joint. Synovial fluid is a lubricating fluid that supplies nutrients and oxygen to cartilage.
Cartilage. The cartilage is a slippery tissue that coats the ends of the bones. Cartilage is composed of four components:
|Click the icon to see an image of the synovial membrane and cartilage in the knee joint.|
Review Date: 06/16/2010
Reviewed By: Reviewed by: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.