Occulta - Sometimes called "Hidden Spina Bifida". The spinal cord and the nerves are usually normal and there is no opening on the back. In this usually harmless form of spina bifida, there is a small gap in a few of the vertebrae that make up the spine. The underlying neural tube defect is covered completely with skin. Although there may be no motor or sensory impairments evident at birth, subtle, progressive neurologic deterioration often becomes evident in later childhood and adulthood. Frequently, there are telltale signs on close examination of the back. In many cases, spina bifida occulta is so mild that there is no disturbance of spinal function at all. This form occurs in 3-5 percent of the population and people often don't even know they have it.

Meningocele - The meninges (protective covering of the spinal cord) come through the open part of the spine like a sac that is pushed out. Cerebrospinal fluid is in the sac and there is usually no nerve damage. Individuals with this form suffer minor disabilities; however new problems can develop later in life.

Myelomeningocele - This occurs when the meninges and spinal nerves come through the open part of the spine. This is the most serious type of spina bifida, which causes nerve damage and more severe disabilities. Hydrocephalus (water on the brain), often occurs in 70-90 percent of children with myelomeningocele. This happens when the cerebrospinal fluid, which cushions and protects the brain and spinal cord, is unable to drain normally because of the birth defect. Fluid collects in and around the brain, causing the head to become enlarged. Implanting a shunt into the ventricals of the brain, with tubing leading into the abdominal cavity, will allow the fluid to drain from the brain.