Neural tube defects affecting the brain

The four forms of dysraphias in the brain region correspond to those mentioned for the spinal cord. In cranium bifidum occultum, there is a defect of a single bone either in the frontal or in the occipital region. Meningocele is a protrusion of the meninges within a hernial sac through the open cranium. In encephalomeningocele, the hernial sac also includes brain tissue. Anencephaly is the worst form of cerebral dysraphia. The brain is freely exposed and unprotected at the surface. In addition, the prosencephalon, mesencephalon and the rostral part of the rhombencephalon are usually missing. Newborns with anencephaly cannot survive.