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an extraembryonic fetal membrane, composed of trophoblast lined with mesoderm; it develops villi, becomes vascularized, and forms the fetal part of the placenta.
chorion frondo´sum the placental part of the chorion; it is covered by villi.
chorion lae´ve the nonvillous, membranous part of the chorion.
the nonvillous, membranous part of the chorion where the chorionic villi have degenerated.
Synonym(s): chorion laeve
The smooth, nonvillous portion of the chorion.
See also: chorion