During the early embryonic development, the neural tube forms and serves as the precursor of the central nervous system, particularly the brain and the spinal cord. There are instances wherein defects occur involving the neural tube. One of these defects is the spina bifida, which particularly affects the spinal cord. Spina bifida is a defect characterized by the failure of the backbone and membranes surrounding the spinal cord to close completely. When the posterior neuropore of the neural tube failed to close, eventually exposing the spinal cord is specifically referred to as rachischisis.
There are two main types of rachischisis: (1) rachischisis totalis and (2) rachischisis partialis. In rachischisis totalis, also referred to as holorachischisis, the entire spinal cord is exposed. In rachischisis partialis, there is a portion of the spinal cord that is closed and a portion that is flayed open.1 The rachischisis totalis is the more severe form of rachichisis.
Word origin: Greek rachis (spine) + schizein (to split) + totalis (total, entire)
1 Haines, D. & Ard, M. (2013). Fundamental neuroscience for basic and clinical applications. Philadelphia, PA: Elsevier/Saunders.