Meningocele: Protrusion of the membranes that cover the spine and part of the spinal cord through a bone defect in the vertebral column. Meningocele is due to failure of closure during embryonic life of bottom end of the neural tube, the structure which gives rise to the central nervous system (the brain and spinal cord). The term spina bifida refers specifically to the bony defect in the vertebral column through which the meningeal membrane and cord may protrude (spina bifida cystica) or may not protrude so that the defect remains hidden, covered by skin (spina bifida occulta). However, through usage the term spina bifida is gradually becoming synonymous with Meningocele. The risk of Meningocele (and all neural tube defects) can be decreased by the mother eating ample folic acid during pregnancy.