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Right costophrenic angle

The right costophrenic angle is the acute recess formed between the right hemidiaphragm and the right lateral chest wall (costal pleura). It represents the most inferior lateral extent of the right pleural cavity and is a key surface and imaging landmark in thoracic anatomy and radiology.

It is routinely assessed on chest imaging because subtle changes at this angle are often the earliest indicators of pleural or basal pulmonary processes.

Synonyms

  • Right costodiaphragmatic angle

  • Right pleural recess (costophrenic recess)

Location

  • Located at the inferolateral aspect of the right hemithorax

  • Formed by the junction of the right costal pleura and right diaphragmatic pleura

  • Lateral to the right hemidiaphragm

  • Inferior to the right lower lobe of the lung

  • Approximately at the level of the 8th–10th ribs in the midaxillary line (varies with respiration)

Anatomical components

  • Costal pleura

  • Diaphragmatic pleura

  • Underlying right hemidiaphragm

  • Adjacent basal segments of the right lower lobe

Relations

Superiorly:

  • Right lower lobe of the lung

Inferiorly:

  • Right hemidiaphragm

  • Subdiaphragmatic structures (liver, via diaphragm)

Laterally:

  • Inner surface of the right thoracic cage

Medially:

  • Basal lung parenchyma

X-ray appearance

Chest radiograph (PA / AP view):

  • Right costophrenic angle: Sharp, acute, well-defined angle

  • Diaphragmatic contour: Smooth dome-shaped outline

  • Comparison: Normally slightly higher than the left due to the liver

  • Lateral view: Posterior costophrenic recess seen as a sharp posterior angle

CT appearance

Lung window:

  • Right costophrenic angle: Sharp interface between aerated lung and pleural space

  • Basal lung parenchyma: Normal aeration extending to the pleural margin

  • Pleural recess: Appears as a thin potential space without soft-tissue density

  • Diaphragm: Smooth muscular contour separating thoracic and abdominal cavities

Mediastinal window:

  • Pleural surfaces: Thin and closely apposed

  • No soft-tissue thickening at the angle

MRI appearance

T1-weighted images:

  • Lung parenchyma: Low signal intensity

  • Pleural space: Potential space with low signal

  • Diaphragm: Intermediate signal intensity muscle

T2-weighted images:

  • Lung parenchyma: Low signal due to air content

  • Pleural recess: Low signal

  • Diaphragm: Intermediate signal with clear separation from lung

STIR:

  • Lung and pleural space: Low signal

  • Diaphragm: Intermediate signal

  • Useful for assessing fluid or soft-tissue changes at the costophrenic recess

CT image

Right costophrenic angle ct Anatomy, Location and Imaging Appearance

X-Ray image

Right costophrenic angle x ray Anatomy, Location and Imaging Appearance -img-00000-00000