Vitellointestinal duct (vitelline duct, yolk stalk): channel connecting the apex of the midgut loop (future ileum) to the yolk sac.
Normally disappears (obliterates) completely by the 10th week of intrauterine life; its anomalies result from partial or complete failure of this obliteration.
Formation and Normal Involution
Forms as the wide communication between midgut and yolk sac narrows to the definitive vitelline duct at the apex of the U-shaped primary intestinal loop.
This wide communication is first established when the primitive gut forms in the 4th week of intrauterine life, during folding of the embryo.
Anomalies of the Vitellointestinal Duct
Anomalies of the vitellointestinal duct, by site of persistence