Bones change with age. They become less elastic and more brittle. The joints between bones may become rough as the cartilage wears out. Long bones, like those in your legs and arms, increase in length from growth plates at the end. Bone growth stops when you become an adult.
Arthritis means joint swelling, pain, and loss of motion.
There are more than 100 kinds of disease that can cause arthritis. The most common forms of arthritis are osteoarthritis, rheumatoid arthritis, and gout. Less common forms are psoriatic and septic arthritis. Osteoarthritis is also know as degenerative joint disease. It is caused by injury or years of use.