Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Small right apical pneumothorax measuring 5 mm in diameter . Subcutaneous air seen in the right chest wall . Heart size is normal . Left lung is clear . Linear atelectasis / scarring seen in posterior basal aspect of the left lower lobe .
    OUTPUT:
    
Small residual right pneumothorax measuring 5 mm in diameter .