Conventional frontal and lateral chest X-rays, supplemented by a picture in the lateral decubitus position with a horizontal beam, are usually sufficient to explore the pathology of the pleura and the chest wall. Ultrasound is particularly helpful for demonstrating localized fluid accumulation and locating the diaphragm; it does not irradiate the patient and can be used at the bedside. CT scan provides highly contrasted images and a picture of the anatomy on the entire depth of the transverse plane. Resonance magnetic imaging, thanks to its ability to provide high resolution pictures in the frontal, sagittal and transverse planes, is especially useful for the study of regions of highly complex anatomy, such as the pulmonary apex and brachial plexus. The use of radionuclides is rarely required for demonstration of loculated pleural effusion. More prospective studies are needed to determine the respective yield of each of these techniques.