Notochord and spinal malformations.

Fourteen spinal malformations were found in 328 spontaneously aborted human embryos and fetuses. Of these, 13 were investigated histologically and histomorphometrically and compared with 47 age- and stagematched normal specimens to document any possible relationship between spinal and notochordal malformations. Although six notochordal malformations, such as bifurcation, were found in 14 spinal malformations, the respective sites did not correspond. Abnormality of notochordal tissue--such as degeneration and delayed development, which was observed in nine of 14 spinal malformations--was not restricted to the site of the spinal malformation. Moreover, tissue changes responsible for spinal malformations usually did not occur in direct contact with the notochord. On the other hand, malformed notochords were found in normal specimens. We therefore were unable to confirm in human specimens that notochordal abnormalities induce spinal malformations, a fact well established in lower vertebrates.