Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest were provided demonstrating pneumomediastinum as well as subcutaneous emphysema extending into the right and left upper chest wall . Overall findings appear stable from prior exam . There is no pneumothorax , effusion , or signs of pneumonia . The heart size is normal . Bony structures are intact .
    OUTPUT:
    
Pneumomediastinum and subcutaneous emphysema in the upper chest wall . Findings could reflect small airways injury . No pneumothorax or pneumonia .