Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest . Lungs are clear without consolidation , effusion , or pneumothorax . The cardiomediastinal silhouette is within normal limits . Well - circumscribed radiopacity projects over the lateral aspect of left first rib , thought to be external in nature . No acute osseous abnormality is identified . No free air below the diaphragm .
    OUTPUT:
    
No free intraperitoneal air nor acute cardiopulmonary process .