<prompt> Least common site of lung abscess is -Left upper lobeLeft lower lobeRight upper lobeRight lower lobe  <response>: About the site of lung abscess associated with aspiration, Schwartz writes - Because of the effect of gravity, foci of infection tend to develop in the subpleural regions of the superior segments of the lower lobes and in the posterior segments of the upper lobes.The right lung is involved more frequently, presumably because of the less acute angle of the right main bronhus. thus the right upper and lower lobes are the most commonly affected, followed by the left lower lobe and right middle lobe. 