Joints are the areas where two or more bones meet. Most joints are mobile, allowing the bones to move. Joints consist of the following:

Cartilage – at the joint, the bones are covered with cartilage (a connective tissue), which is made up of cells and fibers and is wear-resistant. Cartilage helps reduce the friction of movement.

Synovial membrane – a tissue called the synovial membrane lines the joint and seals it into a joint capsule. The synovial membrane secretes synovial fluid (a clear, sticky fluid) around the joint to lubricate it.

Ligaments – strong ligaments (tough, elastic bands of connective tissue) surround the joint to give support and limit the joint’s movement.

Tendons – tendons (another type of tough connective tissue) on each side of a joint attach to muscles that control movement of the joint.

Bursas – fluid-filled sacs, called bursas, between bones, ligaments, or other adjacent structures help cushion the friction in a joint.

Synovial fluid – a clear, sticky fluid secreted by the synovial membrane.

Joint Pain Associated with Arthritis

Arthritis Joint Pain ( – The word arthritis literally means joint inflammation, but it is often used to refer to a group of more than 100 rheumatic diseases that can cause joint pain, stiffness, and swelling in the joints. These diseases may affect not only the joints but also other parts of the body, including important supporting structures such as muscles, bones, tendons, and ligaments. Two of the most common forms of arthritis are osteoarthritis and rheumatoid arthritis (

Most forms of arthritis are associated with joint pain that can be divided into two general categories: acute and chronic. Acute pain is temporary, lasting a few seconds or longer. Chronic pain, such as that seen in people with osteoarthritis and rheumatoid arthritis, ranges from mild to severe and can last weeks, months, and years to a lifetime. More than 40 million Americans are affected by some form of arthritis, and many have chronic joint pain that limits daily activity. Osteoarthritis is by far the most common form of arthritis, affecting over 20 million Americans, while rheumatoid arthritis, which affects about 2.1 million Americans, is the most disabling form of the disease.

What Causes Joint Pain?

The joint pain ( associated with arthritis may come from different sources. These may include inflammation of the synovial membrane (tissue that lines the joints), the tendons, or the ligaments; muscle strain; and fatigue. A combination of these factors contributes to the intensity of the joint pain.

Arthritic joint pain varies greatly from person to person. Factors that contribute to the joint pain include swelling within the joint, the amount of heat or redness present, or damage that has occurred within the joint. In addition, activities affect joint pain differently so that some patients note joint pain after first getting out of bed in the morning, whereas others develop joint pain after prolonged use of the joint. Find detailed information on Joints and Joint Pain Products (


What is Cartilage?

Cartilage is the key to healthy joints. Cartilage is the spongy tissue that cushions the ends of the bones within the joints. Although cartilage is composed of 65 to 80 percent water, there are three other important components that make up the rest of cartilage tissue: collagen, proteoglycans, and chondrocytes.

Collagen: a fibrous protein. Collagen is also the building block of skin, tendon, bone, and other connective tissues.

Proteoglycans: a combination of proteins and sugars. Strands of proteoglycans and collagen weave together and form a mesh-like tissue. This allows cartilage to flex and absorb physical shock.

Chondrocytes: cells that are found all through the cartilage. They mainly help cartilage stay healthy and grow. Sometimes, however, they release substances called enzymes that destroy collagen and other proteins. Researchers are trying to learn more about chondrocytes.

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