Spina bifida means open spine. The spine (backbone) protects the spinal cord, a bundle of nerves that runs down the middle of your back. The spinal cord carries signals back and forth between your body and your brain. Spina bifida happens when the bones in the spine don’t form correctly, or when the spinal cord doesn’t form correctly, leaving a gap or opening. Spina bifida can happen anywhere along the spine.Spina bifida is the most common kind of neural tube defect (also called NTD). NTDs are birth defects of the brain and spinal cord. Birth defects are health conditions that are present at birth. Birth defects change the shape or function of one or more parts of the body. They can cause problems in overall health, in how the body develops or in how the body works.A baby’s neural tube normally develops into the brain and spinal cord. It starts out as a tiny, flat ribbon that turns into a tube by the end of the first month of pregnancy. NTDs happen if the tube doesn’t close completely. About 1,500 to 2,000 babies are born with spina bifida each year in the United States.