Introduction Introduction of foreign material into the lungs Specific lobe of lung involved depends on the position of the patients supine superior segment of right lower lobe standing/sitting posterobasal segment of right lower lobe lying on right side right middle lobe or posterior segment of right upper lobe (as seen in image) More often seen in the right lung than the left result of wider and straighter right mainstem bronchus Risk factors altered mental status seizure disorders, severe dementia, alcoholism impaired cough reflex impaired swallowing