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spina(spi'na) plural.spinae [L. spina, thorn]
1. Any spinelike protuberance.
2. The spine.
spina bifidaSpina bifida cystica.
spina bifida cystica
A congenital defect in the walls of the spinal canal caused by a lack of union between the laminae of the vertebrae during embryonic development. The lumbar portion is the section chiefly affected. It is found in approx. 18 of every 100,000 births. Like other neural tube defects, it can be prevented with folic acid supplementation (800 mg daily) taken by women before and during pregnancy. The consequences of this defect may include urinary incontinence, saddle or limb anesthesia, gait disturbances, and structural changes in the pelvis. Synonym: rachischisis
spina bifida occulta
A failure of the vertebrae to close without hernial protrusion.