Vitelline duct

Vitelline duct
Fetus of about eight weeks, enclosed in the amnion. (Vitelline duct labeled at lower right.)
Sketches in profile of two stages in the development of the human digestive tube. (Vitelline duct labeled on bottom image.)
Gray's	subject #10 54
Days	28
Precursor	midgut, yolk sac
MeSH	Vitelline+Duct

In the human embryo, the vitelline duct, also known as the omphalomesenteric duct, is a long narrow tube that joins the yolk-sac to the digestive tube. It appears at the end of the fourth week, when the yolk-sac presents the appearance of a small pear-shaped vesicle (the umbilical vesicle).

The vesicle can be seen in the afterbirth as a small, somewhat oval-shaped body whose diameter varies from 1 mm to 5 mm. It is situated between the amnion and the chorion and may lie on or at a varying distance from the placenta.

As a rule the duct undergoes complete obliteration during the seventh week, but in about two per cent of cases its proximal part persists as a diverticulum from the small intestine, Meckel's diverticulum, which is situated about two feet above the ileocecal junction, and may be attached by a fibrous cord to the abdominal wall at the umbilicus.

Sometimes a narrowing of the lumen of the ileum is seen opposite the site of attachment of the duct.

Additional images

Front view of two successive stages in the development of the digestive tube.

External links

• yolk+stalk at eMedicine Dictionary