Spina bifida malformations fall into four categories: spina bifida occulta, spina bifida cystica (myelomeningocele), meningocele and lipomeningocele. The most common location of the malformations is the lumbar and sacral areas of the spinal cord. Myelomeningocele is the most significant form and it is this that leads to disability in most affected individuals. The terms spina bifida and myelomeningocele are usually used interchangeably.