1. Embryologic failure of fusion of vertebral arches and neural tube with consequent exposure of neural tissue at the surface; spina bifida cystica with myelocele or myeloschisis. 2. Spinal dysraphism. [G. rhachis, spine, + schisis, division]
- r. partialis SYN: merorachischisis.
- r. totalis SYN: holorachischisis.
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ra·chis·chi·sis rə-'kis-kə-səs n, pl -chi·ses -kə-.sēz a congenital abnormality (as spina bifida) characterized by a cleft of the spinal column
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n.
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ra·chis·chi·sis (ra-kisґkĭ-sis) [rachi- + -schisis] congenital fissure of the vertebral column; see also spina bifida.Medical dictionary. 2011.