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spine (def. 1).
spina bi´fida a developmental anomaly characterized by defective closure of the bony encasement of the spinal cord; the spinal cord and meninges may or may not protrude through the defect (see spina bifida cystica and spina bifida occulta). It is further classified according to the extent of neural involvement (see meningocele and meningomyelocele). See also neural tube defect.
spina bi´fida ante´rior a defect of closure on the anterior surface of the bony spinal canal, often associated with defective development of the abdominal or thoracic viscera.
spina bi´fida cys´tica spina bifida in which there is protrusion through the defect of a cystic swelling that contains the meninges (meningocele) or the meninges and spinal cord (meningomyelocele).
spina bi´fida occul´ta spina bifida in which there is a defect in the bony spinal canal without protrusion of the cord or meninges.
spina vento´sa dactylitis of the bones of the hands or feet, occurring mostly in infants and children, with enlargement of digits, caseation, sequestration, and sinus formation.
cryptomerorachischisis(krĭp″tō-mē″rō-ră-kĭs′kĭ-sĭs) [″ + meros, part, + rhachis, spine, + schisis, a splitting]
Spina bifida occulta without a tumor but with bony deficiency.