Anthropological Study of the Sacrum of the Korean Fetus

The author has anthropologically measured 26 items on the sacra of 365 Korean fetuses ranging from the 4th to the 10th fetal months. computed 14 indices and determined their parameters, and the following conclusions have been drawn. 1). The longitudinal and transverse diameters of the sacrum increase about 4 times during above ranging period. 2). The form of the sacrum is dolichohieric and changes from long slender to short broad with the fetal month in approaching to the adult type. 3). The longitudinal and transverse diameters of the sacral arc increase about 4 times during above ranging period. 4). The greatest height of the sacral arc increases about 7 times during above ranging pericd. 5). The longitudinal curvature of the sacral arc changes stronger quickly with the fetal month in approaching to the adult type. but no change is found in the transverse curvature. 6). There is no change in the location of the greatest height of the sacral arc with the fetal month and it locates lower than that of the adult. 7). The longitudinal and transverse diameters of the auricular surface increase about 4 and 5 times respectively during above ranging period. 8). The form of the auricular surface changes from long slender to short broad with the fetal month in approaching to the adult type. 9). The location of the auricular surface is hypobasal as in the adult. 10). The longitudinal and transverse diameters of the sacral canal increase about 6.5 and 3.5 times respectively during above ranging period. 11). The form of the entrance of the sacral canal changes from flat anteroposteriorly to oval transversely with the fetal month in approaching to the adult type. 12). The longitudinal and transverse diameters cf the sacral base increase about 3.5 and 4 times respectively during above ranging period. 13). The form of the sacral base changes from weak to strong oval transversely with the fetal month in approaching to the adult type. 14). The breadths between the sacral foramina increase about 3.2 times respectively during above ranging period. 15). The thicknesses of the sacral vertebrae increase about 3.2 times respectively during above ranging period. 16). No change is found in the angle of the promontory with the fetal month and it is smaller than that of the adult. 17). There are no differences in the fetal sacrum between both sexes and the sex differences in the sacrum occur after birth. 18). No differences are found in all of the items and indices between both right and left sides