Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear . There is no pleural effusion or pneumothorax . The cardiomediastinal silhouette is within normal limits . There is a large hiatal hernia . Right 4th rib deformity , presumably from prior thoracotomy , is unchanged .
    OUTPUT:
    
No acute intrathoracic process . Large hiatal hernia .