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KMID : 0376219690060010061
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Chonnam Medical Journal
1969 Volume.6 No. 1 p.61 ~ p.77
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The Prenatal Development of the Vertebral Column in Korean Fetuses
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Abstract
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Histological and radiological studies were made on the development of vertebrae in the human fetuses ranging from 7mm. to 55cm. CH. length and portions of the spinal cords in each level were determined at the various developmental stages of the fetus. Results were obtained as follows.
1. Caudal end of the spinal cord, situated at the caudal border of coccygeal vertebrae at the beginning of the second-lunar age of the fetus, reached the Ievel of the third lumbar vertebra or the lower margin of the second` at the end of 10th month (or just before birth)
2. Theventro-dorsaldiameter of the lumbar enlargement was greater than that of the cervical on and after the 5th month. The cervical enlargement extended from the fourth to the sixth cervical vertebra and lumbar enlargement were from 10th to 12th thoracic vertebra during whole fetal life.
3. Primordia of the vertebrae at the 7cm. CH. length were blastemal and intervertebraIprimordia could be distinguished from those cf body of vertebrae by the cell populations in unit area, which were greater in the former than the latter. Chondrification of the body Of the vertebra was completed by the time when fetal length became 22mm.
4. The ossification centers, one in each arch and one in the body, were first seen in the- verstebraeof 7.2cm. fetus. Total fourteen centers of ossification were present simultaneously in the vertebral column of 7.2cm. fetus. and as the fetal month proceeded, ossification was gradually extended to the cervical and sacral vertebrae from thoracic and lumbar ver tebrae where the ossification centers were already present in earlier fetal month and linr upper cervical and lower sacral vertebrae, the ossification was occured last.
The ossification process in the body appeared to be preceded by that in the arch.
5. Cartilagenous plates made their appearance on the cranial and dorsal surface of the vertebral body in 23cm, fetus and remained until birth as longitudinal growing portion of the vertebrae.
6. Intervertebral discs were composed of lamina of fibrous tissue, fibrocartilage and notochord. Throughout the fetal life, outermost fibrous ring and layers of fibrocartilage in the ventral portion were much more compact than those of the dorsal.
7. Cartilagenous canals in the body of vertebrae were abundant in the region, where the ossification was actively progressing. The cartilagenous node, Schmorl´s node, could not be demonstrated in the vertebrae during the whole series of the study.
Results described above largely confirmed those of previous reports on the of her races, although, in this study, special attention was made on the structures of intervertebral discs correlating them with directionof herniated nut leus pulposus in the adult. Also included were the evidences to support that longitudinal growth ofthe vertebral body took.
ace by means of truew epiphyseal cartilage plates.
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