Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Localizing history was not provided . There is a mildly displaced fracture at the posteriolateral aspect of the right eighth rib . No additional rib fractures are clearly identified . No fracture seen on the left . There is slightly increased opacity at the left lung base on the frontal view , likely representative of atelectasis . The cardiac and mediastinal silhouettes appear within normal limits . There no focal pulmonary opacities , pleural effusions , or pneumothorax .
    OUTPUT:
    
Mildly displaced posteriolateral right eighth rib fracture . Atelectasis at the left base .