VARIATIONS IN DEVELOPMENT OF CAUDAL NEURAL TUBE IN HUMAN EMBRYOS (HORIZONS 14-21)

Eight human embryos of Streeter's Horizons XIV to XXI were examined with respect to variations in caudal neural tube development after closure of the posterior neuropore in Horizon XII. A major aspect of this development appears to be a process of “canalization” (accessory lumens coalescing from the differentiating caudal neural cell mass), which corresponds to such occurrences in the chick and rat. Some degree of obliteration of the central canal was found in four embryos. The relation of these observations to clinical entities is discussed. There is suggestive evidence that open lesions of the spine may be associated with failure of closure of the posterior neuropore. In contrast, normal‐skin covered lesions probably arise from neural tube formed from the differentiating caudal cell mass after Horizon XII. This hypothesis could explain the distribution of lesions seen in newborn children. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company