spina bifida cystica

spina bifida cys·ti·ca (sst-k)

n.

Spina bifida with protrusion of the meninges or spinal cord.

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spina bifida cystica,

a developmental defect of the central nervous system in which a hernial cyst containing meninges (meningocele), spinal cord (myelocele), or both (myelomeningocele) protrudes through a congenital cleft in the vertebral column. The protruding sac is encased in a layer of skin or a fine membrane that readily ruptures, causing the leakage of cerebrospinal fluid and an increased risk of meningeal infection. The severity of neurologic dysfunction and associated defects depends directly on the degree of nerve involvement. The most severe type is lumbosacral myelomeningocele, which is frequently associated with hydrocephalus and the Arnold-Chiari malformation. Compare spina bifida occulta. See also myelomeningocele, neural tube defect.

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spina

pl. spinae [L.] spine; a slender process such as occurs on many bones.

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spina bifida

a developmental anomaly characterized by defective closure of the two halves of the vertebral arch through which the spinal cord and meninges may or may not protrude.

spina bifida cystica

spina bifida in which there is protrusion through the defect of a cystic swelling involving the meninges (meningocele), spinal cord (myelocele) or both (meningomyelocele).

spina bifida occulta

spina bifida in which there is a defect of the bony spinal canal without protrusion of the cord or meninges.

spina bifida ventralis

a defect of closure on the ventral surface of the bony spinal canal, often associated with defective development of the abdominal and thoracic viscera.