Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright and lateral views of the chest provided . Lungs are clear . No large effusion or pneumothorax . A retrocardiac opacity is again noted which likely reflects known hiatal hernia . Cardiomediastinal silhouette is stable . Bony structures appear intact . Chronic left clavicle deformity noted .
    OUTPUT:
    
No acute findings .