Development of the descending colon during the human foetal period.

The growth, changes in shape, topography and relation to the peritoneum of the descending colon were assessed on the basis of material taken from 178 foetuses of both sexes, aged from 72 to 236 days of pregnancy. The statistical analysis method demonstrated that the descending colon growth process occurs about a month earlier in female foetuses as compared to male ones. From the statistical point of view, the longitudinal growth of the descending colon significantly slows down in the 7th and 8th months of pregnancy, while the width of this part of the large intestine increases sharply towards the end of the foetal development period. The statistically important process of the descending colon rising over the surface of the left kidney and adrenal gland was noticed in male foetuses. This occurs approximately one month earlier in female foetuses as compared to males. The ascent of this part of the colon is accompanied by a change in its shape from straight, to curved and, finally, to wavy in the oldest age group of male foetuses. The changes in relation to the peritoneum are manifest in a gradual change in the position of this section of the intestine from the intraperitoneal, where more than 40% of the cases examined had a fully movable mesentery, to the extraperitoneal, with 14% of foetuses having a mesentery in the 8th month of pregnancy.