protoduodenum

The first part of the duodenum, which extends from the gastroduodenal pylorus as far as the major duodenal papilla and develops from the caudal foregut of the embryo; it has no plicae circulares and is the seat of the duodenal glands.

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pro·to·du·o·de·num (pro″to-doo″o-deґnəm) the first or proximal portion of the duodenum, extending from the pylorus to the duodenal papilla, and developed embryonically from the foregut.