In order to understand joint pain, it’s important to understand the various components that make up a joint. A joint is the articulation between two bony surfaces that allows for movement at the two surfaces. The joint itself is comprised of cartilage that allows for smooth and gliding motion. There’s also a capsule that acts as a covering around the cartilage that helps stabilizes the joint. On the inside of the capsule is the synovial membrane which produces joint lubricating synovial fluid. This combined structure allows for easy, flowing motion and increased stability. There are also other structures of the joint outside of the capsule, including various ligaments (which attach bone to bone) and tendons (which attach muscle to bone). Bursas allow for decreased friction between tendons and bones.
What causes joint pain?
Joint pain can be caused by various conditions. One condition that people often talk about is rheumatoid arthritis. Rheumatoid arthritis is a chronic inflammatory disease that affects the synovial lining which produces synovial fluid. This is an autoimmune disease, in other words, the body is mistaking its own parts as things it needs to attack. It forms immunoglobulins that attack and cause damage the body. The symptoms of rheumatoid arthritis include inflammation and swelling of the synovial tissue, the joints may become painful, stiff, and swollen.
One important characterization of rheumatoid arthritis is that the inflammation, pain, and swelling is often symmetric – it happens on both sides. This is in contrast to osteoarthritis, which occurs with wear and tear on a joint. For example, if you are right handed, you will experiences more wear and tear over your lifetime on your right hand, your right wrist, your right fingers, your right elbows, and your right shoulders because that is your dominant hand. Because rheumatoid arthritis is an inflammatory systemic disease and it does not care which side it chooses, and it often will affect both sides of the body.
As mentioned, joint pain can be caused by wearing down of the cartilage (osteoarthritis). This is the most common condition that causes joint pain. Other causes of joint pain can include the muscles, the tendons, the ligaments, and the bursa. These structures are located outside of the joint itself. It is important to realize that all of these structures work together as a unit to allow for joint motion. When a problem occurs in one area, it can often have a cascade effect on other areas. For example, if you have arthritis and you start developing a limp because of the pain associated with the arthritic condition, you may start to put stress on the tendons, muscles, and ligaments not only in that joint but in joints of adjacent areas. This is why it is very important that when you have pain you should get it addressed sooner rather than later because of this domino effect, the pain in one area can cause pain in another area that could have been avoided had the primary area been treated.