Cranioschisis

Cranioschisis (Greek: κρανιον kranion, "skull", and σχίσις schisis, "split"), or dysraphism, is a neural tube defect involving the skull. In this defect, the cranium fails to close completely (especially at the occipital region). Thus, the brain is exposed to the amnios and eventually degenerates, causing anencephaly.^{[citation needed]}

Craniorachischisis is on the extreme end of the dysraphism spectrum, wherein the entire length of the neural tube fails to close.^[1]