Radiographic appearance of lobar collapse

The changes to the chest radiograph that may be expected in lobar collapse are described: changes in density; changes in position; and alterations in the appearances of borders. Pure lobar collapse is rare and the features described only represent a guide. The appearances of collapse of each lobe are described in detail. Examples of radiographs and line drawings describing the movements of the fissures are included. There is a brief comment on subsegmental collapse.