COMPLETE LEFT PERICARDIAL DEFECT WITH DUAL PASSAGE OF THE PHRENIC-NERVE - A CHALLENGE TO THE WIDELY ACCEPTED EMBRYOGENIC THEORY

We report a patient with complete left pericardial defect whose phreni c nerve, split into two portions, passes both ventral and dorsal to th e defect. The dorsal part of the phrenic nerve passes over the ventral surface of the pulmonary artery and veins, indicating that the perica rdio-pleural foramen has been obliterated. Contrary to the widely acce pted embryogenic theory that pericardial defect results from persisten ce of the pericardiopleural foramen, we consider that the defect in th is patient resulted from a tear in the pericardio-pleural membrane imm ediately lateral to the common cardinal vein.