An encephalocele (in-sef-a-luh-seal) is a rare disorder in which the bones of the skull do not close completely. This creates a gap through which cerebral spinal fluid, brain tissue and the meninges (the membrane that covers the brain) can protrude into a sac-like formation.
An encephalocele (sometimes called a cephalocele or meningoencephalocele) is classified as a neural tube defect. The neural tube is the tissue of an embryo that becomes the brain, spinal cord and bones surrounding each. (Embryo is term used to describe a developing baby to the eighth week after conception).
A meningocele is an encephalocele that contains only the meninges and cerebral spinal fluid. These types of defects have a much better prognosis than those in which brain tissue also protrudes into the sac.