This document discusses several joint and connective tissue diseases including osteoarthritis, rheumatoid arthritis, osteomyelitis, and septic arthritis. Osteoarthritis is characterized by the progressive deterioration of articular cartilage in the joints. It is the most common joint disease and has minimal inflammation. Rheumatoid arthritis is an autoimmune disease that causes inflammation of the synovial membrane in multiple joints. Osteomyelitis is a bone infection that is usually caused by Staphylococcus aureus. Septic arthritis refers to a bacterial infection that causes inflammatory destruction of joints.