spina bifida(n = noun.state) rachischisis, schistorrhachis - a not uncommon congenital defect in which a vertebra is malformed; unless several vertebrae are affected or there is myelomeningocele there are few symptoms; can be diagnosed by amniocentesis;
A congenital malformation in which the spinal column is cleft at its lower portion, and the membranes of the spinal cord project as an elastic swelling from the gap thus formed. [1913 Webster]