Chest X-ray Abnormalities Lobes, fissures and contours
Key points
Knowing the anatomical structures adjacent to the fissures, diaphragm and heart contours can help determine where disease is located without the need for a lateral view
Disease within the right middle lobe may obscure the right heart border, or may be limited by the horizontal fissure, or both
Zones or lobes?
Although it is generally best to refer to the location of lung abnormalities in terms of zones, occasionally you will see signs, that will tell you which specific lobe is involved.
Right middle lobe disease
The right middle lobe is bordered superiorly by the horizontal fissure, and medially by the right heart border. Any abnormality, which increases density of this lobe, may therefore obscure the right heart border, or be limited superiorly by the horizontal fissure.
The right heart border (right atrial edge) is obscured
Consolidation (asterisk) is limited above by a crisp line, formed by the horizontal fissure
The pathology must therefore involve the right middle lobe
More extensive shadowing also involves the right and left peri-hilar regions
Clinical information
Child with a cough and fever
Diagnosis
Pneumonia involving the right middle lobe
Horizontal fissure displacement
Displacement of the horizontal fissure may be another indicator of the location of pathology. If the fissure is displaced upwards, this may be because of volume loss of the right upper lobe, for example due to collapse, or fibrosis. If the horizontal fissure is displaced downwards, there may be a process which has caused volume loss of the right lower lobe.
