Anatomical Variability of the Colon in Human Fetuses

The incidence of congenital malformations and chronic diseases of the digestive system has increased for the recent years. A special place in the occurrence of digestive system pathology belongs to individual anatomical variability and abnormalities of the colon development. At the present stage of the fetal surgery development there is a need for further elucidation of age and individual anatomical variability of the colon in human fetuses of different ages, as well as of the morphological prerequisites for the possible occurrence of its birth defects. The purpose of the study was to elucidate the various anatomy of the colon in human fetuses aged 6-7 months. Materials and methods. A macroscopic study of the typical and various anatomy of the colon was carried out on 18 specimens of human fetuses with 186.0-270.0 mm of crown-rump length (CRL) by means of anatomical preparation and morphometry. Results and discussion. The study found some variants of the topography of the parts (transverse, descending and sigmoid ones) of the colon in 6-7 month old fetuses. A fetus with 208.0 mm of CRL had parts of the sigmoid colon various in shapes (loop-like, "S" and "C"-shaped ones) and the P-shaped sigmoid colon of width of CRL 260.0 mm had an atypical topography and variant structure of the parts of the colon, in particular, the transverse colon was composed of the right and left upper and lower loops. In this case the descending colon occupied the umbilical region and, partly, the left iliac fossa, while the proximal and distal loops of the sigmoid colon were located in the region of the left and right iliac fossa respectively. The places of transition of the colon parts vary as well. In particular, in a fetus with 208.0 mm of CRL, the transition of the lower colon into the sigmoid colon was identified by 28.0 mm above the anterior superior iliac spine. In a fetus with 260.0 mm of CRL, the transition of the transverse colon into the descending colon was identified by 15.0 mm below the inferior extremity of the left kidney. In the fetuses with 215.0 and 260.0 mm of CRL, the transition of the sigmoid colon into the rectum was identified to the right of the midsagittal plane. Conclusions. Syntopical interactions are intensively manifested in the fetal period of human ontogenesis, as evidenced by the variability of the shape and position of the colon parts in fetuses of both the same and different age groups. In some experimental 6-7 month fetuses there was a variability of both topography and shape of the colon individual parts, which became a morphological prerequisite for the possible occurrence of their malformations. At this stage of development, the formation of the colon continues correlating with the morphogenesis of other organs of the abdominal cavity and pelvis. An aggregate of findings on the development of the shape and topography of the colon individual parts in human fetuses of different ages must be taken into account by fetal and neonatal surgeons during surgical interventions.