costophrenic angle

A small portion of each lung normally reaches into the costophrenic angle.

This can push the lung upwards, resulting in "blunting" of the costophrenic angle.

With pleural effusion, fluid often builds up in the costophrenic angle (due to gravity).

About 175 cc of pleural fluid will cause a blunted costophrenic angle discernible on chest radiography.

Costophrenic angles, including pleural effusions

Bilateral infiltrates on chest radiograph sparing costophrenic angles

In anatomy, the costophrenic angles are the places where the diaphragm (-phrenic) meets the ribs (costo-).

The costophrenic angle is abnormally deepened when the pleural air collects laterally, producing the deep sulcus sign.

In effusions, the fluid layers out (by comparison to an up-right view, when it often accumulates in the costophrenic angles).

The lesion usually has calcification, poorly defined and irregular borders, and associated blunting of the costophrenic angles.

An interesting aspect of this finding is the generally minimal nature of costophrenic angle blunting usually found with larger pleural effusions.

In a supine position chest X-ray the 'deep sulcus sign' is diagnostic, which is characterized by a low lateral costophrenic angle on the affected side.

At least 300 ml of fluid must be present before upright chest films can pick up signs of pleural effusion (e.g., blunted costophrenic angles).

[189] The pleural fibrosis is often progressive, resulting in restrictive lung defects, especially if the costophrenic angle is obliterated.

It often extends over the area of an entire lobe or lung, with fibrotic areas involving costophrenic angles, apices, lung bases, and interlobar fissures.

Blunting of costophrenic angle (in adults)-Loss of sharpness of one or both costophrenic angles.

Patients with chronic obstructive pulmonary disease (COPD) may exhibit deepened lateral costophrenic angles due to hyperaeration of the lungs and cause a false deep sulcus sign.

There needs to be at least 75ml of pleural fluid in order to blunt the costophrenic angle on the lateral chest radiograph, and 200ml on the posteroanterior chest radiograph.

Pleural thickening may cause blunting of the costophrenic angle, but is distinguished from pleural fluid by the fact that it occurs as a linear shadow ascending vertically and clinging to the ribs.

The latter may be evident in chest X-rays with micronodular and interstitial infiltrate in the mid and lower zone of lung, with sparing of the Costophrenic angle or honeycomb appearance in older lesions.

In accordance with the International Labor Organisation (2000) classification, diffuse pleural thickening is considered to be present if there is obliteration of the costophrenic angle in continuity with 3 mm pleural thickening.

This finding must be distinguished from blunting of the costophrenic angle, which may or may not represent a small amount of fluid within the pleural space (except in children when even minor blunting must be considered a finding that can suggest active TB).