Chest x-ray anatomy
Costophrenic recesses and angles
The costophrenic recesses are formed by the hemidiaphragms and the chest wall. They contain the rim of the lung bases which lie over the dome of each hemidiaphragm. On a frontal chest x-ray the recess is seen in only one place on each side, where an angle is formed by the lateral chest wall and the dome of each hemidiaphragm. These angles are known as the costophrenic angles.
Key points
- The costophrenic angles are limited views of the costophrenic recess
- On a frontal view the costophrenic angles should be sharp
Costophrenic recesses and angles on a frontal view
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Costophrenic angles
On a PA view, the costophrenic recesses are seen on each side as the costophrenic angles. The costophrenic angles consist of the lateral chest wall and the dome of each hemidiaphragm.
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Costophrenic recesses and angles on a lateral view
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Anterior and posterior costophrenic angles
On a lateral view the costophrenic recesses are seen in the region of the anterior and posterior costophrenic angles formed by the chest wall and the dome of each hemidiaphragm.
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Assessing the costophrenic angles
On a frontal chest x-ray the costophrenic angles should form acute angles which are sharp to a point.
Often the term costophrenic "blunting" is used to refer to the presence of a pleural effusion. This, however, is not always correct and costophrenic angle blunting can be related to other pleural disease, or to underlying lung disease. Lung hyper-expansion can also lead to blunting of the costophrenic angles. This is because the domes of the diaphragm are pushed downwards and so the angle formed is no longer acute.