Arthritis, itself a group of more than 100 different diseases, is one category of rheumatic diseases.

Arthritis and other rheumatic diseases are characterized by pain, swelling, and limited movement in joints and connective tissues in the body.

Rheumatic diseases are the leading cause of disability among people ages 65 and older.

Diagnosing arthritis and other rheumatic diseases is often difficult, as many symptoms are similar among the different diseases.

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

Sprained ankles and wrists, arthritic knees and hips and torn rotator cuffs all have one thing in common: They result in joint pain.