Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiograph demonstrates unremarkable cardiomediastinal and hilar contours . Lungs are clear . No pleural effusion or pneumothorax is evident . Multiple posterior healed rib fractures are identified on the left . No acute displaced rib fractures are visualized .
    OUTPUT:
    
No acute intrathoracic process . Multiple healed posterior left rib fractures .