It may be associated with other birth defects, such as spina bifida cystica.

Spina bifida is further divided into two subclasses, spina bifida cystica and spina bifida occulta.

Spina bifida malformations fall into three categories: spina bifida occulta, spina bifida cystica with meningocele, and spina bifida cystica with myelomeningocele.

Complex congenital abnormalities within the same organ (for example, tetralogy of Fallot) or sequences (for example, spina bifida cystica with hydrocephalus and clubfoot, or diaphragmatic defect with lung hypoplasia and dextrocardia) were classified as isolated.

Neural Tube Defect SB Spina Bifida Cystica Spina Bifida Occulta Spina bifida is characterized by incomplete closure of certain bones of the spinal column (vertebrae), leaving a portion of the spinal cord exposed.