Topographical anatomy of Spiegel's lobe and its adjacent organs in mid-term fetuses: Its implication on the development of the lesser sac and adult morphology of the upper abdomen.
At 8-16 weeks of gestation, Spiegel's lobe of the caudate lobe appears as a sac-like herniation of the liver parenchyma between the inferior vena cava and ductus venosus or Arantius' duct. In 5 of 11 fetuses at 20-30 weeks of gestation, we found that an external notch was formed into the posterior aspect of the caudate lobe by a peritoneal fold containing the left gastric artery. This notch appeared to correspond to that observed in adults, which is usually seen at the antero-inferior margin of the lobe after rotation of the lobe along the horizontal or transverse axis. However, the notch did not accompany two of the three fetuses in which the left hepatic artery originated from the left gastric artery. Notably, until 9-10 weeks of gestation, the inferior and left part of Spiegel's lobe rode over the hepatoduodenal ligament and protruded medially into the lesser sac (bursa omentalis) behind the stomach. Thus, the fetal Winslow's foramen was located at the "superior" side of the ligament. However, as seen in adults, the protruding Spiegel's lobe was located at the posterior side of the lesser omentum. Therefore, a hypothetical rotation along the transverse axis in the later stages of development seems necessary to explain this repositioning. Considering that Spiegel's lobe develops faster than surrounding structures, it is likely that the lesser sac resulting from the rotation of the gastrointestinal tract, which actively contributes to facilitate the growth of the Spiegel lobe.
Hwang
Si Eun
SE
Department of Surgery, Medical School, Chonbuk National University, Jeonju, Korea.
Cho
Baik Hwan
BH
Hirai
Ichiro
I
Kim
Hyoung Tae
HT
Kim
Ji-Hyun
JH
Fujimiya
Mineko
M
Murakami
Gen
G
Kimura
Wataru
W
D000005:Abdomen / Q000196:embryology*; D005260:Female; D047109:Fetal Development / Q000502:physiology*; D005865:Gestational Age; D006503:Hepatic Veins / Q000033:anatomy & histology; D006801:Humans; D008099:Liver / Q000098:blood supply / Q000196:embryology*; D008102:Liver Circulation / Q000502:physiology; D008297:Male; D009852:Omentum / Q000196:embryology*