RT Journal Article T1 Regressing vitelline vein and the initial development of the superior mesenteric vein in human embryos A1 Abe, Hiroaki A1 Yamamoto, Masahito A1 Yanagisawa, Nobuaki A1 Morimoto, Ryoichi A1 Murakami, Gen A1 Rodríguez Vázquez, José Francisco A1 Abe, Shinichi AB The superior mesenteric vein was considered to develop in situ in the midgut mesentery secondary to regression of the left vitelline vein. We revisited the morphology using serial sections of 20 embryos at 5-6 weeks (CRL 9-15 mm). The regressing vitelline vein provided a long peritoneal fold in the immediately superior side of the midgut mesentery containing the thick superior mesenteric artery. Notably, in a half of specimens, there were tissue clefts along the superior mesenteric artery in the mesentery and they were communicated with the left vitelline vein at the superior end of the peritoneal fold. The tissue clefts appeared not to carry the endothelial lining. We considered the cleft as the initial superior mesenteric vein. Conversely, the initial vein seemed not to develop from budding or venous plexus. PB Tokyo Editional Board of Okajimas Folia Anatomica Japonica SN 1881-1736 YR 2017 FD 2017 LK https://hdl.handle.net/20.500.14352/109690 UL https://hdl.handle.net/20.500.14352/109690 LA eng NO Abe, H., Yamamoto, M., Yanagisawa, N., Morimoto, R., Murakami, G., Rodríguez-Vázquez, J. F., & Abe, S. (2017). Regressing vitelline vein and the initial development of the superior mesenteric vein in human embryos. Okajimas folia anatomica Japonica, 94(3), 87–92. https://doi.org/10.2535/ofaj.94.87 DS Docta Complutense RD 7 abr 2025