Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable AP upright chest radiograph ___ at 09 :01 is submitted .
    OUTPUT:
    
Interval appearance of extensive subcutaneous emphysema involving the chest wall and neck soft tissue as well as pneumomediastinum . No pneumothorax is seen . Lungs remain grossly clear . Overall cardiac and mediastinal contours are stable . No free intraperitoneal air is seen beneath the diaphragm .