Rachichisis is a rare form of the neural tube birth defect Spina Bifida where there is a cleft or "split" along the entire length of the spine.
The suffix for the medical term rachischisis is -schisis, which means a fissure or splitting.
From the Related link below:Myelomeningocele - most severe form with spinal cord exposureMeningocele - a severe form with the meninges protruding outside the spine under the skin of the backOccult spina bifida - the mildest form with often a small spinal defect often in the lower back