IN cranium bifidum, a congenital or traumatic defect of the skull, the cranial contents herniate, causing what is variously called a meningocele, cephalocele, encephalocystocele, etc. In the literature these terms are often used interchangeably. Although, strictly speaking, a cranial meningocele does not contain brain, neural elements are usually found in the wall.
Cranial meningocele is much rarer than spinal meningocele and constitutes only 10% of central nervous system hernias. Cranial meningoceles are of two types: the sincipital, which form external tumefactions, and the basal. Located within the nose or pharynx, between 5% and 10% of cranial meningoceles are reported to be of the basal type. Among 546 patients with meningocele at the Boston Children's Hospital, Ingraham and Swan1 found 84 to be cranial, and among these 64 were occipital, 9 were parietal, 6 were frontal, and only 5 (6%) were endonasal.
—A basal meningocele usually exits from
LEWIN ML, SHUSTER MM. Transpalatal Correction of Basilar Meningocele With Cleft Palate. Arch Surg. 1965;90(5):687-693. doi:10.1001/archsurg.1965.01320110023005