[Morphometric studies on the cortex and medulla of frontally sectioned kidneys in the Japanese adult].

The cortex and medulla areas, sectioned frontally, of 50 kidneys from 25 dissecting cadavers were measured to determine the correlation between differences in sex, laterality, and age. The average parenchyma (cortex + medulla) area was 33.45 +/- 9.16 cm2 and was larger in men than women; there was no significant laterality, but the parenchyma area was negatively correlated with age. The average cortex area was 20.39 +/- 5.80 cm2 and was also larger in men than women; laterality was not significant, and the cortex area was negatively correlated with age. The average medulla area was 13.05 +/- 4.40 cm2, and no significant difference in sex or laterality was found. The medulla area was negatively correlated with age. Additionally, the average number of renal pyramids (medulla) was 6.24 +/- 1.45 on these sections. Difference in the average areas of cortex and medulla was significant. The medulla was exceptionally larger in two cases (4%). The ratio between the average area of the cortex and medulla (C/M ratio) was 1.67 +/- 0.56. No sex difference or laterality was found, nor was there a correlation between the C/M ratio and age or kidney size. The sectioned area of cortex was approximately 1.5 to 2 times larger than medulla. These results suggest that senile atrophy may occur at the same rate in the renal cortex as in the medulla.