The human nervous system develops from a small, specialized plate of cells (the Neural plate) along the back of an embryo. Early in fetal development, the edges of this plate begin to curl up toward each other, creating the neural tube-a narrow sheath that closes to form the brain and spinal cord of the embryo. As development progresses, the top of the tube becomes the brain and the remainder becomes the spinal cord. This process is usually complete by the 28th day of pregnancy. But if problems occur during this process, the result can be brain disorders called neural tube defects, including Spina Bifida.
