Also known as craniolacunia /Luckenschadel skull. The term lacunar skull signifies a dysplasia of the membranous bone with well-defined lucent areas in the calvaria that correspond to nonossified fibrous bone. The lacunae are bounded by normally ossified bone. The appearance resolves spontaneously by age 6 months and is not related to the degree of concurrent hydrocephalus. Lacunar skull is associated with neural tube defects, especially myelomeningocele with Chiari II malformation,and less commonly with encephalocele. The multiple well-defined areas of relative lucency in the cranium must be distinguished from the increased convolutional markings that develop with pansynostosis at an older age.