Abstract
The following is a summary of a quantitative study of the growth of 70 external dimensions of the human body in the fetal period. Of these dimensions, 22 were of the head and neck, 28 of the trunk and pelvis, 16 were of the extremities, and 4 involved more than one major division of the body. Each dimension was determined from a series of preserved specimens, the number of cases ranging from 207 to 369.
Each dimension was plotted against the crown-heel or total body-length. In 19 instances the resulting curves approximated straight lines; in 41 instances the curves approximated straight lines, except at their upper ends. In 9 instances the relation could be approximated by two straight lines meeting in about the middle of the distribution. In one instance the relation in the lower ranges was expressed by a straight line, and in the upper by a curved one.
It was found that the departure from a straight line of the 41 curves mentioned above was due to the effects of birth moulding, to changes in the form of the chest following birth, and to formalin artifacts. Experimental studies were made of each of these factors. Corrections for head moulding were determined by the measurements of heads of children delivered by Cesarean section, and second twins born with breech presentation. The chest changes were determined by measurements of living newborn infants. The changes produced by formalin artifacts were also worked out quantitatively. The application of the corrections thus obtained to the upper values for the dimensions of this group reduced these curves to straight lines. The remaining 9 dimensions were mainly measurements in the anterior median line of the body.
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