“Encephalocele a rare type of birth defect of the neural tube that affects the brain. The neural tube is a narrow channel that folds and closes during the third and fourth weeks of pregnancy to form the brain and spinal cord. Encephalocele is a sac-like protrusion or projection of the brain and the membranes that cover it through an opening in the skull. Encephalocele happens when the neural tube does not close completely during pregnancy. The result is an opening anywhere along the center of the skull from the nose to the back of the neck, but most often at the back of the head (pictured), at the top of the head, or between the forehead and the nose.  Allowing it to sac out of the skull.”

Centers for Disease Control and Prevention CDC