Chest X-ray Anatomy
Costophrenic recesses and angles

Key points

  • The costophrenic angles are limited views of the costophrenic recess
  • On a frontal view the costophrenic angles should be sharp

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.

Costophrenic recesses and angles - PA view

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Costophrenic recesses and angles - PA view

  • On a PA view, the costophrenic recesses are seen on each side as the costophrenic angles
  • The costophrenic angles are formed by the lateral chest wall and the dome of each hemidiaphragm

Costophrenic recesses and angles - lateral view

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Costophrenic recesses and angles - lateral view

  • 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.

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.