Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A single portable semi-erect chest radiograph was obtained . Lung volumes are low , accentuating the lung markings . Retrocardiac opacity may reflect atelectasis or consolidation . No effusion or pneumothorax is identified . A non-displaced left lateral rib fracture is visualized .
    OUTPUT:
    
Low lung volumes limit evaluation . No pneumothorax . Non-displaced left lateral rib fracture .