Symptomatic arthritic and enthesopathic conditions of the sternum and its articulations have not been studied well as a group, despite previous reports of individual diseases and radiographic abnormalities that affect these structures. The lack of a unified clinical approach has been partly due to the absence of a name for the clinical condition, which we propose to call juxtasternal arthro-osteitis. Although juxtasternal arthro-osteitis may be caused by septic arthritis, this study was based on 24 adult patients with noninfectious juxtasternal arthro-osteitis, collected retrospectively from records of patients who had sternal tomography and from rheumatology clinic populations. Twelve of the patients had an underlying systemic arthropathy that met standard diagnostic criteria; three patients had an unclassifiable systemic arthropathy; and nine patients had the idiopathic localized disease, which has been termed sternocostoclavicular hyperostosis. Radiographic findings in the various diseases followed definite trends, but were not sufficiently distinct to provide the sole basis for diagnosis. Initial failure to correlate dermatologic, rheumatologic, radiographic, and laboratory findings led to prolonged delays in diagnosis in many cases. When juxtasternal arthro-osteitis is encountered, a thorough evaluation should be made for systemic disease. Idiopathic sternocostoclavicular hyperostosis can be diagnosed only after systemic arthropathy or enthesopathy has been excluded.