File:Human fetal pancreas anatomy cartoon.jpg

Fetal topographical anatomy of the pancreatic head and duodenum with special reference to courses of the pancreaticoduodenal arteries

A diagram showing joining processes between the dorsal and ventral primordia of the pancreas as well as the hypothetical rotation of the duodenum along a left-right axis. Viewed from the posterosuperior side of the body. A horizontal plane including most parts of the duodenum is shown to emphasize, in contrast to adults, the course of the second portion (D2) directing posteriorly rather than inferiorly. The topographical anatomy of the duodenum and pancreatic head is based on observations of fetuses of 20-30 weeks (e.g., Figs. 3,4,5 and 6). The anterior mass of the pancreatic head (labeled by dots) seems to correspond to the dorsal primordium of the pancreas, while an oblique or perpendicular posterior mass [labeled by sharps (#)] seems to primarily correspond to the ventral primordium. The portal vein and right hepatic artery run in the superior sides of and along their border between the anterior and posterior masses. Notably, tongue-like protrusions of the anterior mass or dorsal pancreas (stars) surround the primary posterior mass or the ventral pancreas. In particular, the right anterior protrusion (open star) often reaches the inferior end of the ventral pancreas. The common bile duct crosses the superior side of the first portion of the duodenum. We hypothesize a rotation along a left-right axis through the third portion of the duodenum in the later stage of development. In addition, the fourth portion is connected by a fascia (asterisk) to a thick fascia along the left renal vein.

PURPOSE: The purpose of this study is to provide better understanding as to how the "double" vascular arcades, in contrast to other intestinal marginal vessels, develop along the right margin of the pancreatic head. MATERIALS AND METHODS: In human fetuses between 8-30 weeks, we described the topographical anatomy of the vessels, bile duct, duodenum as well as the ventral and dorsal primordia of the pancreatic head with an aid of pancreatic polypeptide immunohisto-chemistry. RESULTS: The contents of the hepatoduodenal ligament crossed the superior side of the pylorus. Moreover, the right hepatic artery originating from the superior mesenteric artery ran along the superior aspect of the pancreatic head. An arterial arcade, corresponding to the posterior pancreaticoduodenal arteries, encircled the superior part of the pancreatic head, whereas another arcade, corresponding to the anterior pancreaticoduodenal arteries, surrounded the inferior part. The dorsal promordium of the pancreas surrounded and/or mixed the ventral primordium at 13-16 weeks. Thus, both arterial arcades were likely to attach to the dorsal primordium. CONCLUSION: The fetal anatomy of the pancreaticoduodenal vascular arcades as well as that of the hepatoduodenal ligament were quite different from adults in topographical relations. Thus, in the stage later than 30 weeks, further rotation of the duodenum along a horizontal axis seemed to be required to move the pylorus posterosuperiorly and to reflect the superior surface of the pancreatic head posteriorly. However, to change the topographical anatomy of the superior and inferior arterial arcades into the final position, re-arrangement of the pancreatic parenchyma might be necessary in the head.

Original File Name: Fig. 7 Ymj-51-398-g007-l.jpg

Reference

<pubmed>20376893</pubmed>| Yonsei Med J.

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