[Obstruction and normal rechannelization of the ureter in the human embryo. Relations to stenoses and congenital ureteral valves].
Study of 5 normal human embryos from 5 to 55 mm in length from vertex to coccyx, shows that the ureteric ducts, which in the first phases of development are permeable (embryos of 5-13 mm, Streeter's Horizons XIII-XVII, age from 28 +/- 1 to 35 +/- 1 days), constantly undergo a process of obstruction and a subsequent recanalization of their lumen, which takes place when the embryos measure from 14 to 22 mm. The processes begin in the middle zone of the ureters and progress proximally and distally until they cover its entire length. These ducts, which in embryos of approximately 17 mm in length form solid cords, are totally permeable in embryos of 23 mm. These modifications are of great importance for correct interpretation of the pathogenic mechanism of congenital ureteric strictures and valves.
D006801:Humans; D007231:Infant, Newborn; D014513:Ureter / Q000002:abnormalities / Q000196:embryology*; D014517:Ureteral Obstruction / Q000151:congenital*
Obstruction et recanalisation normales de l'uretère chez l'embryon humain. Relations avec les sténoses et les valvules uretérales congénitales.