How does spina bifida develop in the vertebral column?

Spina bifida is a congenital neural tube defect characterized by the failure of the vertebral column to close properly over the spinal cord.12

During normal embryonic development, the neural tube—the precursor to the central nervous system—folds and closes along the back of the fetus. Simultaneously, cells from the sclerotome migrate to enclose the neural tube, forming the blastema of the vertebral neural (dorsal) arch. Spina bifida occurs when this process is disrupted; specifically, the vertebrae fail to form or fuse completely over the back of the spinal cord, leaving the underlying nerve tissue unprotected.23

This condition most frequently affects the sacral or lumbar regions, which are the final sections of the neural tube to close during development. Depending on the severity of the failure, the spinal cord may remain covered by skin (as in spina bifida occulta) or, in more serious cases, protrude through the vertebral defect, potentially exposing nervous tissue or the meninges to the surface.2