When the right upper lobe collapses there is increased opacity in the right upper zone, which is delineated inferiorly by the horizontal fissure. As collapse progresses the fissure moves and bows upwards. Right upper lobe collapse is less visible on the lateral film as the upper zone is often partly obscured by the overlying shoulders and upper arms.
Right upper lobe collapse is less visible on the lateral film as the upper zone is often partly obscured by the overlying shoulders and upper arms. This example (from a different patient) demonstrates the triangular opacity of the upper lobe.
The changing appearance of right upper lobe collapse is elegantly shown by a series of chest radiographs ranging from normal to complete collapse.
A variation is Golden's S sign, when there is a bulge at the lower margin of the collapsed lobe, due to the causative hilar carcinoma.
This image demonstrates right upper lobe collapse due to a right hilar carcinoma. The right hilar enlargement is clearly visible.
Right lower zone shadowing is combined with obliteration of the hemidiaphragm (silhouette sign). This needs to be differentiated from a pleural effusion. The right heart border, which is anterior, is usually still clearly seen (silhouette sign again). The oblique fissure lies more horizontally and may become visible, giving a sharp upper margin to the shadowing. If the lobe collapses completely, it may appear as a triangular opacity behind the right heart border. The heart border, being anterior will still be clearly seen.
On the lateral film there is abnormally increased density over the lower thoracic spine due to the triangular opacity of the collapsed lobe. Do not confuse the anterior borders of the scapulae (soild arrows) with the oblique fissures. The right oblique fissure is displaced downwards and now outlines the collapsed lobe (open arrows).
Ill defined shadowing is evident adjacent to the right heart border, which becomes indistinct.
This is often not immediately obvious on the frontal film, but when suspected, is a good indication for a lateral film. The collapsed lobe is clearly seen as a thin wedge between the horizontal and oblique fissures, which are displaced.
