Micro-angiographical studies of the medullary venous system of the cerebral hemisphere.

In order to identify the zones of convergence of the medullary veins of the cerebral white matter, gelatin-mixed barium sulfate was injected into normal brains at autopsy. A catheter was inserted into the internal jugular veins or the carotid and vertebral arteries. Serial soft tissue roentgenograms of whole brains and brain slices were used to determine the zones of convergence. The deep med-ullary veins had four zones of covergence before draining into the subependymal veins: the first (superficial), second (candelabra), third (palmate) and fourth (subependymal). The zones of various convergence within the white matter were due to the crossing of nerve fiber tracts (e.g. the pes of the corona radiata, the radiation of the corpus callosum, the superior occipitofrontal fasciculus, the tapetum and the sagittal strata). Similar but less conspicuous information about the parenchymal arteries was observed in the arterial injection studies. These results suggest that micro-angiographical studies of the medullary veins of the cerebral white matter provide detailed information on veno-architecture and convergence zones. This information may help in understanding the pathogenesis of medullary venous malformations.