Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single supine AP portable view of the chest was obtained . An endotracheal tube is seen , terminating approximately 0 .3 cm above the level of the carina . There is no evidence of pneumothorax . The lungs are clear without focal consolidation . No pleural effusion is seen . A radiopaque structure measuring 3 - 4 mm is seen projecting over the medial thorax at the level just superior to the posteromedial right ninth rib , difficult to discern whether internal or external to the patient .
    OUTPUT:
    
1 . Endotracheal tube in appropriate position . 2 . 3 - 4 mm radiopaque structure projecting just superior to the level of the posteromedial right ninth rib , unclear whether external or internal to the patient .