Timetable for Intestinal Rotation in Staged Human Embryos and Fetuses

Won Kyu Kim, Hyun Kim, Dae Ho Ahn, Myoung Hee Kim, Hyoung Woo Park

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

BACKGROUND: The existing data on intestinal rotation during human development are contradictory regarding the timing of major events, and as such an exact timetable for rotation of the intestine in humans is not yet available. METHODS: We studied the initial formation and rotation of the intestine by microdissection and histological observations in 72 human embryos and fetuses at two to 12 weeks postfertilization. The embryos were classified according to the Carnegie staging system. RESULTS: The primordium of the primitive gut was first observed as a yolk sac at stage 5. With the formation of the embryonic foldings, three divisions of the primitive gut (the foregut, midgut, and hindgut) were observed at stage 10. At stage 12, the primitive gut was located on the midline. At stage 15, a 90° counterclockwise rotation of the intestine began. At stage 16, herniation of the intestine into the umbilical cord was not evident in observations of the external form or a transversely sectioned embryo, but was evident in a sagittally sectioned embryo. There was another 90° counterclockwise rotation at stage 20. Reduction of the intestine was a rapid process, since it was still in the cord in fetuses of <40 mm crown-rump length (CRL), and was reduced above 40 mm in general during nine weeks of development. When the intestine returned to the abdominal cavity, the cecum was located in the right lower quadrant (the adult position). CONCLUSIONS: We have developed a standard timetable to describe the rotation of the intestine. The current results will be helpful in studies describing the pathogenesis of some developmental abnormalities in the intestine due to abnormal rotation.

Original languageEnglish
Pages (from-to)941-945
Number of pages5
JournalBirth Defects Research Part A - Clinical and Molecular Teratology
Volume67
Issue number11
DOIs
StatePublished - 2003 Nov 1

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