Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are relatively low . The lungs are clear . Skin fold overlying the left lung apex mimics a pneumothorax . Blunting of the right posterior costophrenic angle is compatible with a small pleural effusion . The cardiomediastinal silhouette is within normal limits . No displaced acute fractures . Deformity of the proximal left humerus suggests prior healed fracture .
    OUTPUT:
    
Probable small right pleural effusion . No superimposed acute cardiopulmonary process .