Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lungs are well expanded clear . Mediastinal contour , hila , and cardiac silhouette are normal . The aorta is tortuous . No pneumothorax or pleural effusion . Left fifth posterior rib fractures appears chronic .
    OUTPUT:
    
Chronic left fifth rib fracture . No evidence of acute fracture within the limits of plain radiography .