The right hemidiaphragm is slightly higher than the left
The liver is located inferior to the right hemidiaphragm
The stomach and spleen are located inferior to the left hemidiaphragm
The hemidiaphragm contours do not demarcate the lowest part of the lungs
The diaphragm separates the lungs from the abdominal organs. The abdominal organs are more dense (whiter) than the air-filled lungs (blacker). Each hemidiaphragm should appear as a smooth, domed contour.
The right hemidiaphragm is usually a little higher than the left. The liver is located immediately inferior to the right hemidiaphragm. The stomach and spleen are located immediately inferior to the left hemidiaphragm.
The stomach is frequently visible as a gas-filled 'bubble' below the left hemidiaphragm. It is important to be aware that the lowest portion of the lungs – which occupy the posterior costophrenic recesses – extend below the level of the contours of the hemidiaphragms. The stomach bubble forms a window through which this part of the lung is visible on the left.
Lateral X-rays show the right hemidiaphragm extending from posterior to anterior
The left hemidiaphragm becomes indistinct at the lower edge of the heart and the stomach bubble may be seen below it
Assessing the diaphragm
The hemidiaphragms are domed structures that should be well defined and visible to the midline on a frontal view. The contours of the hemidiaphragms do not demarcate the bottom of the lungs; lung markings can be seen below the hemidiaphragms. This area of the lungs should be checked whenever assessing a chest X-ray.
Inferior displacement of the diaphragm is a sign of lung hyperexpansion.
Raised position of a single hemidiaphragm may indicate phrenic nerve palsy.
