What Is A Joint?

A joint is an area where two or more bones come together connected by ligaments, which are thick bands of tissue. The most commonly affected joints by arthritis are the hip and knee.

The hip is a ball-and-socket joint. The ball is the upper portion of the thighbone, known as the femoral head, and the socket is the rounded area of the pelvis, known as the acetabulum. The knee is formed by the thighbone, known as the femur and the shinbone, known as the tibia.

The ends of these bones are covered with cartilage, which is smooth, soft, durable tissue. Healthy cartilage allows smooth, frictionless movement that we hardly notice. The remaining area of the joint is covered by a thin, smooth tissue called the synovium. Here, fluid is produced that acts as a lubricant to reduce wear and tear on the joint.