Fetal membrane morphology and circulation of the liquor amnii.

Morphological study of the human fetal membranes (at the term of pregnancy) shows that under the amniochorion lies the chorionic cytophoblast, which completely surrounds the amniotic cavity. Chorionic cytotrophoblast as well as parietal decidua persist until full term and remain well-developed. Within trophoblastic cells there are numerous canalicular formations bordered by microvilli resembling those observed between amniotic cells. The authors therefore believe that the circulation of amniotic fluid, after traversing the amnion, will continue through the intercellular canaliculi of the chorionic cytotrophoblast to reach the decidua parietalis. All the components of this complex membrane must play a part in the amniotic fluid circulation.