Juvenile idiopathic arthritis (JIA) is a serious autoimmune childhood disease that encompasses several types of chronic arthritis. It is the most common rheumatic disease in children and can cause significant short-term and long-term disability, including permanent joint damage. Management of JIA is based on a combination of pharmacologic interventions, physical and occupational therapy, and psychosocial support. Intra-articular steroid (IAS) injection, or injection of steroid medication into an arthritic joint, is a routine therapeutic procedure in clinical rheumatology. Most pediatric rheumatologists currently perform injections based on knowledge of anatomy and by feeling for anatomical landmarks, but results from adult studies on ultrasound (US)-guided technique have suggested a role for using US in treating and managing JIA. The overall goal of this project is to determine the feasibility of a multicenter study comparing US-guided IAS injection with the usual technique of using external anatomic features to improve arthritis symptoms in JIA. The key issues that this pilot project will determine will be: 1) the ability to use US to successfully image and detect abnormalities in the joints in children with JIA 2) image the injected medication in the joint space or its surroundings immediately after the injection 3) determine methods to measure the clinical response to injection 4) evaluate the feasibility of using saved US scans to localize injected medication in or around the joints and to determine abnormalities concerning for arthritis. These results will be used to establish the protocols necessary to design a multicenter study to determine the effect of US-guided IAS injection in the treatment of juvenile arthritis. Studies regarding the applicability and feasibility of musculoskeletal US in an outpatient pediatric rheumatology setting are important in order to establish the utility of this new technology in guiding diagnosis and therapy in JIA. Results from this study may have a significant impact on pediatric rheumatology and the way by which pediatric rheumatologists currently assess signs of arthritis and perform routine therapeutic procedures.