Spina bifida or hydrorrhachitis is a congenital malformation consisting of a cleft in the vertebral column with protrusion of the lining membranes of the spinal cord.
This deformity is caused by an arrest of ossification of the vertebral arches, and is situated in any region of the vertebral column. It is more frequently found in the lumbar region, which constitutes about 50 per cent. of all cases; there are probably about 12 per cent, in the lumbo-sacral region, and about 25 per cent. in the sacral region. It is frequently associated with other congenital deformities, such as hydrocephalus, talipes, harelip, etc.
It consists of a tumor, varying in size from a marble to an adult's head, and occupies the central portion of the canal over the posterior aspect of the vertebral column, and is intimately connected with the canal in which a gap is felt in the bones of the
EVE PF. SPINA BIFIDA OR HYDRORRHACHITIS.. JAMA. 1901;XXXVII(10):627–628. doi:10.1001/jama.1901.62470360019001f