A few cases of delayed absorption in bones of the skull following head injury have been described. Pancoast, Pendergrass and Schaeffer1 reported a case in which an unusual alteration in bony structure developed after a fracture of the skull, with hernia of the cerebrum and elevation of a fragment of bone from the cranium. Rowbotham2 described a defect in the vault of the skull with traumatic malacia or absorption of bone following a closed head injury. The thinning and scalloping of bone adjacent to a comminuted fracture of the skull, characteristic of traumatic cyst of the leptomeninges, is not unusual. It was well portrayed by Dyke3 and has been duplicated in our series of head injuries. However, in a review of the literature we have been able to find no instance of a defect in the inner table of the skull alone with herniation of the brain