The joints that move freely around each other, or the synovial joints, have fluid that bathes the soft cartilage pads on each end of the bone. This fluid is held in place by a joint capsule, formed of tough fibers pierced by nerves that lead to muscles around the joint. The capsule can become inflamed, and when this happens, moving the joint creates pain in and around the joint and the amount of movement possible will decrease as time goes on. As the inflammation continues, the body tries to heal the capsule, which thickens it and reduces movement even more. The most common places for this to occur are the shoulder (Frozen Shoulder Syndrome) and the knee (Pilca Syndrome).