The yolk duct ( ductus omphaloentericus , ductus vitellinus ) is a formation in vertebrate embryos and connects the yolk sac with the midgut . The passage is initially a wide opening but becomes narrow and long as the embryo grows.
In the human embryo, the yolk duct usually recedes in the sixth week of pregnancy. With a frequency of 2 to 4%, a small part remains and forms a bulging of the ileum , the Meckel's diverticulum . The duct can also remain open over its entire length and form a connection from the intestine to the navel (umbilical or yolk duct fistula) so that intestinal contents can escape at the navel. In rare cases, the intestine can push its way out through this fistula . If connective tissue strands form at both ends of the yolk duct and a large cyst develops in the middle part, one speaks of an enterocystoma or yolk duct cyst. Since the strands pull through the body cavity, they can lead to strangulation or twisting of the intestine.
- Thomas W. Sadler: Medical Embryology . 10th edition. Thieme, ISBN 3-13-446610-4 , p. 322-335 .