Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP view of the chest . There is a small amount of subcutaneous air along the left lateral chest . The mentioned rib fractures are not well evaluated on this study . Bibasilar atelectasis . Previously seen pneumothorax is not well seen . There is an abnormal mediastinal contour explained by mediastinal fat on CT .
    OUTPUT:
    
No definite pneumothorax is seen , meaning it is likely not larger . Subcutaneous air adjacent to the left lateral ribs . Abnormal mediastinal contour is explained by mediastinal fat .