[Marginal atelectasis of the lower lobes (author's transl)].

During one year ward films showed opacities with sharp upper margins at the borders of the upper and lower lobes in 17 seriously ill patients, aged between 67 and 87 years. These were interpreted as marginal atelectases of the lower lobes; they have not been previously described. Hypoventilation, with incomplete expansion and marginal atelectasis in seriously ill patients in bed first affect the lower lobes, according to the laws of respiratory physiology and pathology. Marginal atelectasis of the lower lobes occurs unilaterally or bilaterally and in the early stages is reversible. Radiologically, it is clearly distinguishable from intralobar effusions into the major fissure. Other differential diagnosis, such as small pneumothoraces or overlying soft tissue shadows, are not a significant problem.