Venous lakes in the suboccipital dura mater and falx cerebelli of infants: surgical significance.

At birth, 25% of infants have relatively large venous channels coursing in the mid-line of the suboccipital dura mater. They connect the confluence of sinuses with the marginal sinuses. These are limited to the midline suboccipital dura mater in some, whereas in others they implicate the contiguous falx cerebelli as well. These fetal channels gradually shrink, dwindle, or otherwise disappear, and are absent in adolescents and adults. When performing a bilateral suboccipital craniectomy on an infant, one usually divides these venous channels. This may present technical difficulties. Vinylite casts have been made of a series of occipital sinuses. These demonstrated the size, variations, course, and connections of the occipital sinuses and these venous pathways.