neural tube
a structure formed during early development of an embryo, when folds of the neural plate curl over and fuse. Cells of the neural tube differentiate along its length on the anterior–posterior axis to form swellings that correspond to the future forebrain, midbrain, and hindbrain; the posterior part of the tube develops into the spinal cord. The cavity of the tube ultimately becomes the interconnected cerebral ventricles and the central canal of the spinal cord. In neural tube defects, which are a group of congenital defects caused by faulty development of the neural tube from the neural plate, portions of the brain or spinal cord or their covering membranes (the meninges) protrude through a gap in the skull or spinal column, giving rise to neurological disorders, intellectual disability, or physical disability of varying severity. Anencephaly and spina bifida are examples of such defects.
See also neurulation.