Cephaloceles and abnormal venous drainage

Seven cases of parietal cephalocele and three cases of occipital cephalocel e associated with abnormal venous drainage were evaluated, and the mechanis m of the development for venous system was discussed from the embryological viewpoint. In parietal cephaloceles the abnormally draining vein, which co rresponds to the straight sinus, ascended along the interhemisphere apart f rom the tentorium and emptied into the superior sagittal sinus below the ce phalocele. The superior sagittal sinus formed the confluence, which was pos itioned high up. Intraoperative findings revealed that cephalocele penetrat ed the superior sagittal sinus at the midline. In the case of occipital cep halocele, the straight sinus followed a postero-superior course, to drain i nto the confluence just above the neck of cephalocele. The results of our s tudy suggest that the causation of abnormal venous drainage in the great ve in of Galen, the straight sinus and the superior sagittal sinus may be seco ndary, through interaction with a developmentally pre-existing cephalocele.