In radiology, the<unk>  on a supine chest radiograph is an indirect indicator of a pneumothorax. In a supine film, it appears as a<unk> , lucent, ipsilateral costophrenic angle within the nondependent portions of the pleural space as opposed to the apex (of the lung) when the patient is upright. The costophrenic angle is abnormally<unk> ened when the pleural air collects laterally, producing the<unk> . Patients with chronic obstructive pulmonary disease (COPD) may exhibit<unk> ened lateral costophrenic angles due to hyperaeration of the lungs and cause a false<unk> .
Deep sulcus sign
Frontal release sign
Sulcus sign
Cupola sign
White cerebellum sign
Crescent sign
Cingulate island sign
Moniz sign