Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lung volumes are low and there is mild bibasilar atelectasis ; otherwise , the lungs are clear without definite evidence of pneumonia , pleural effusion or pneumothorax . Cardiac and mediastinal silhouette is stable . No displaced rib fractures identified . There is no free air beneath the right hemidiaphragm .
    OUTPUT:
    
No pneumothorax or displaced rib fracture . If there is strong clinical concern for rib fracture dedicated rib series may be performed .