Spina Bifida (Latin: “split spine”) is a developmental congenital disorder caused by the incomplete closing of the embryonic neural tube. Some vertebrae overlying the spinal cord are not fully formed and remain unfused and open. If the opening is large enough, this allows a portion of the spinal cord to protrude through the opening in the bones. There may or may not be a fluid-filled sac surrounding the spinal cord. Other neural tube defects include anencephaly, a condition in which the portion of the neural tube that will become the cerebrum does not close, and encephalocele, which results when other parts of the brain remain unfused.
Spina Bifida malformations fall into three categories: spina bifida occulta, spina bifida cystica with meningocele, and spina bifida cystica with myelomeningocele. The most common location of the malformations is the lumbar and sacral areas. Myelomeningocele is the most significant and common form, and this leads to disability in most affected individuals. The terms spina bifida and myelomeningocele are usually used interchangeably.