ROENTGEN OBSERVATIONS The roentgenogram serves to disclose extracardiac factors for the displacement of the heart. The position of the mediastinal contents and the nature of the shadows in the pulmonary fields indicate whether the displacement is the result of traction of a fibrotic process, tumor or fluid. Mobility of the diaphragm and change in the position of the apex with change of posture signify the absence of pleuropulmonary and diaphragmatic adhesions. In the uncomplicated mirror-picture dextrocardia, the contour of the heart, with definite apex pointing to the right, is the mirror-image of the normal situation and identical with the heart in situs inversus. The course of the aortic arch, however, varies crossing the right bronchus more frequently than the left. In complicated cases the apical region is rounded and the normal cardiac contour modified by the hypertrophy of the right side of the heart, rarely the left, so that distinction