Experimental contribution to the pathogenesis of spina bifida.

Reopening of the central canal in 3-day-old chick embryos results in the development of a typical myeloschisis within 5 min. Focal continuity between the ectoderm and neural tissue at the site of experimentally induced spina bifida (SB) may be achieved in 2 hr and increases in consecutive hours. In 24 hr a secondary neuro-ectodermal junction at the site of SB is fully formed and can be misinterpreted as evidence of a failure of the neural tube to close. Therefore the continuity between ectoderm and neural tube to close. The detachment of the notochord from the open portion of the spinal cord is a secondary phenomenon.