Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are mildly underinflated but clear . Heart size and mediastinal contours are normal . There are surgical clips along the left heart border and intact median sternal wires compatible with prior cardiac surgery . The osseous structures are intact . A marker is placed along the left lateral abdominal wall indicating the site of the patient 's pain , at which there is no discrete abnormality appreciated .
    OUTPUT:
    
1 . Low lung volumes , otherwise clear lungs . 2 . No evidence of rib fracture .