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KMID : 0351619690100010151
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Kyungpook Medical Journal
1969 Volume.10 No. 1 p.151 ~ p.169
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The Growth Analysis of the Vertebral Column and the Extremities in the Later Half of Intra-uterine Life of Korean Fetus
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Abstract
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In a recent series of studies(Joo, 1967, Kim, 1967, Kwak, 1968) we have demonstrated the very wide applicability of the early observation of Zimmermann´s Growth formula(y=a+bt+ct2) that the specific growth rate of mammalians always declines, and of Lairds(1964) that this decline is exponential. All reported measurements of normal and abnormal growth in animals can be accounted for by this model, as can all examples of fetal growth and also tree growth of the component organs and regions of both pre and postnatal animals. In 1932, Huxley demonstrated the generality of a relation that had before that time been recognized for only a few isolated examples of the growth of parts of animals. Known since as the allometric equation, this relation states that the log. of the size of part A bears a linear relation to the log. of the size of part B, or to the size of the whole animals.
The relation may be, and frequently is, given the form y=b:ra, where y is the size of part A, x is the size of part B, and b and a are constants, a is thE: slope of the log. -log. line i, e., b is an index of the size of part A when part B has unit size. Since it was assumed by Huxley that growth is fundamentally a process of self-multiplication of living substance, the allometric equation may Ise interpreted in biological terms as describing a constant correlation, as size increases, between the specific growth rates of the parts being compared.
We had decided to take these formulas in order to study the developmen*_ of the Korean fetus. The len;;th of the vertebral colum and the length of the upper and lower extremities were measured in 109 prenatal cases ranging from 5 to 10 months, and the results were compared with those found in similar investigations by other researcl´Zers in fetus.
The results were as follows:
1) Growth Rate: Generally, the growth rate was observed to be decreased except cervical tebrae, and thoracic vertebrae throughout the er half of fetal life. In vertebral column, wever, the decrease was rapid.
2) Specific Growth Rate: Decrease was in all the experimental groups of vertebral column. per and Iower extremities were very rapid at first, but slowed down as months went by. Lower rimities, cervical vertebrae, thoracic vertebrae, ibar vertebrae, and radial bone in the upper rimities, however, decreased very slowly oughout.
3) The allometry of lumbar and sacro-coccy-geal vertebrae relative to the whole length of vertebral column showed positive allometry, ile that of cervical and thoracic vertebrae awed negative. The growth centers of lumbar and sacro-coccygeal vertebrae were around the 5th month of fetal life, and cervical and thor<~cic vertebrae were around the 10th month of ff~tal life.
4) Of the upper extremities, only the allometry of ulna to the length of the whole upper extremity was positive. The growth centers of humerus and ulna were around the 10th month of fetal life and that of radius was around the 5th month.
5) Of the lower extremities, only the femur showed positive allometry to the length of the whole lower extremity, but all the others showed negative, The growth center of each of the lower extremities was around the 5th month of fetal life,
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