Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are clear given low lung volumes . Cardiomediastinal silhouette is within normal limits . Atherosclerotic calcifications are noted at the aortic arch . Known left - sided pneumothorax is not delineated . Multiple left lateral rib fractures as well as the distal left clavicular fracture are again noted .
    OUTPUT:
    
Known left - sided pneumothorax not identified .