Vitelline duct
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| Vitelline duct | ||
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| Fetus of about eight weeks, enclosed in the amnion. (Vitelline duct labeled at lower right.) | ||
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| 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 | |
At the end of the fourth week the yolk-sac presents the appearance of a small pear-shaped vesicle (umbilical vesicle) opening into the digestive tube by a long narrow tube, the vitelline duct, also known as the omphalomesenteric duct.
The vesicle can be seen in the after-birth 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.
[edit] Additional images
 Front view of two successive stages in the development of the digestive tube. |
[edit] External links
- yolk+stalk at eMedicine Dictionary
