Subdural hematomas (SDH) are a frequent autopsy finding in victims of closed head injuries. About 2/3 of the cases in our own massive SDH series had brain contusions as a cause of bleeding. In about 1/3 of the cases, SDH resulted from ruptured vessels of the brain surface in the absence of contusions. Our experience has shown that such an "isolated" SDH may be expected in about 5% of fatal blunt head injuries. A technique is presented to detect bridging vein leakage before there is any risk of artificial damage. After sawing through the skull in the fronto-occipital plane and cutting through the upper half of the brain together with the calvarium, approximately 5-10 ml of barium sulfate are instilled into the superior sagittal sinus by a balloon catheter at low pressure, and X-rays are taken. If there is extravasation, the rupture is visible before further preparation.