Rheumatoid arthritis (RA) is a common, chronic disease characterised by inﬂammation of the lining of the joint (the synovium), cartilage degradation, and bone erosion. In the early stages of RA, joint pain and swelling are the dominant clinical features. Once acquired, RA persists and over time RA can lead to signiﬁcant joint destruction with loss of function and disability. RA can also affect areas outside the joints (extra-articular manifestations) including rheumatoid nodules, and lung and cardiac involvement. Characteristic features which aid in the diagnosis of RA include the presence of rheumatoid factor (RF) and antibodies against citrullinated peptides in serum, and erosion of bone and cartilage on radiographs of affected joints.