M. Saragababic et al., DIFFERENCES IN ORIGIN AND FATE BETWEEN THE CRANIAL AND CAUDAL SPINAL-CORD DURING NORMAL AND DISTURBED HUMAN-DEVELOPMENT, Acta Neuropathologica, 91(2), 1996, pp. 194-199
Differences in histological appearance between the cranial and caudal
parts of the spinal cord and associated axial organs were analyzed in
9- and 15-week-old human dysraphic fetuses and compared with normal fe
tuses. In human development the cranial part of the neural tube down t
o the lumbosacral level forms during primary neurulation, while its ca
udal part results from secondary neurulation. In the 9-week fetus with
cervical spina bifida, the cranial spinal cord displayed a variety of
morphological changes along the cranio-caudal axis. Spinal cord in th
e upper cervical region transformed into the area cerebrovasculosa, wh
ile the lower cervical and thoracic levels showed only disturbed diffe
rentiation of the cell layers and roof plate. The degree of the crania
l spinal cord dysmorphogenesis correlated with anomalies of the underl
ying notochord and vertebral column. The caudal to lumbosacral region
of the spinal cord appeared normal. In the case of the 15-week-old fet
us with complete dysraphia, the area cerebrovasculosa was found along
the whole extent of the cranial spinal cord, while more caudally, all
axial organs showed a normal histological structure. Our findings conf
irmed a different origin for the cranial and caudal parts of the human
spinal cord. The appearance of dysraphic disorders corresponded to th
e time of primary neurulation; therefore, they resulted in the faulty
formation of the cranial spinal cord. Normally formed caudal spinal co
rd appears during secondary neurulation at later developmental stages.