Rheumatoid arthritis is a chronic systemic inflammatory disease of unknown etiology. It is currently recognized as an autoimmune disease characterized by non-suppurative synovitis of the joints, often with an insidious onset, with joint pain, swelling and morning stiffness as the main symptoms. The first sites are mainly the small joints of the hands and feet, with a bilateral symmetrical distribution. Soft tissue swelling: Soft tissue swelling in the affected joints is often seen in the early and middle stages of arthritis. It is joint-centered, and there is usually no soft tissue calcification. Osteoporosis: Because of the long course of the disease and the large number of joints involved, resulting in bedridden patients who do not see or rarely see daylight, osteoporosis is commonly present in this disease. Joint space changes: Rheumatoid mostly causes narrowing of all joint spaces in the involved joints. In rheumatoid arthritis, joint space enlargement is uncommon and is occasionally seen in the early stages of the disease when there is a lot of fluid accumulation in the joint cavity. Bone changes: In addition to osteoporosis, bone erosion at the edges of the cartilage surfaces and cystic changes in the subchondral bone can be seen, which are quite common in mid- to late-stage lesions. Bone resorption at the bone ends after joint destruction is seen in the small joints of the hands and feet and the acromioclavicular joints. Joint dislocation and deformity: Severe joint destruction and muscle spasm are the causes of joint dislocation, subluxation and deformity, such as drooping deformity of the wrist joint, flexion contracture deformity of the knee joint, ulnar deviation deformity of the metacarpophalangeal joint, gooseneck deformity and buttonhole deformity of the fingers, etc. Joint ankylosis: After the complete destruction and disappearance of the cartilage surface of the joint, fibrous and bony fusion of the joint occurs, making the joint stiff.