Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable frontal view of the chest . The lungs are well expanded and clear without focal opacity suggestive of pneumonia . There is no pleural effusion or pneumothorax . The costochondral junctions are calcified . The aortic knob is calcified . The cardiac size is normal . The hilar and mediastinal contours are normal . No displaced fracture is seen . There are degenerative changes in the acromioclavicular / shoulder joints .
    OUTPUT:
    
No acute intrathoracic process .