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The anal canal muscles development is studied in 18 human embryos. The external anal sphincter results to origin common with the urogenital sphincter from the cloacal sphincter. The muscle, after its appearance, is subdivided into two portions from a thin mesenchymal layer. Moreover, our embryologic study clearly confirms that the puborectalis muscle is a portion of the levator ani, its primordium being common with the ileo and the pubococcygeus muscles. The anal smooth musculature appears later than the striated one.

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Background and Objectives The objective of the present study was to define the location of the most lateral superficial inguinal node lying along the inguinal ligament, through an embryological and anatomotopographical study, in order to rationalize the lateral extension of the groin lymphadenectomy in vulvar cancer. Methods Sections of the upper portion of the femoral triangle belonging to three human fetuses, whose crown‐rump (CR) length ranged from 70 to 310 mm, corresponding to a developmental age of 11 and 35 weeks, were studied. In addition, for an objective topographical evaluation of the disposition of the superficial inguinal lymph nodes, adult cadavers photographs of dissected Scarpa's triangle, reported in anatomical atlases, were analyzed. Results Both the embryological investigation and the anatomotopographical evaluation on cadavers photographs demonstrate that the most lateral superficial inguinal lymph node does not rise above the medial margin of the sartorius muscle, nor far lateral to the point where the superficial circumflex iliac vessels cross the inguinal ligament. Conclusions On the basis of the present study, the authors believe that the superficial circumflex iliac vessels could represent the lateral surgical landmark, easily detectable, at which the inguinal lymphadenectomy should cease. Therefore, there is no need to extend the lateral excision to the anterior superior iliac spine. Finally, leaving the fatty tissue laterally to these vessels, some lymphatic channels could be preserved, decreasing the incidence and the entity of wound seroma and lymphedema. J. Surg. Oncol. 2002;81:19–24. © 2002 Wiley‐Liss, Inc.

The aim of this study was to determine with all possible accuracy the processes of embryologic development of the stomach and its lymphatics in order to confirm their supposed link with the modern anatomic bases of gastric cancer surgery. The knowledge of the anatomic behavior of the peritoneal folds and of the lymphatic drainage of the stomach is, in fact, considered the essential basis for the comprehension of the oncologic dissection of the stomach. The study was based on reconstruction of serial histologic sections of 9 human embryos and 8 human fetuses regarding the mesogastric area, as well as anatomic microdissection of 2 9-month fetuses. The proximal part of the stomach is not involved in the rotation mechanism of the other portions; the lesser sac development follows cranial migration of the spleen; the cardiac (pars cardiaca gastris) area is in continuity with the zone of paraaortic lymph node development; lateral and posterior lymph nodes of the hepatoduodenal ligament do not take origin in the dorsal mesogastrium: they develop together with the common bile duct and the ventral pancreas inside the mesoduodenum; the fusion of the dorsal mesogastrium and the gastric fundus with the posterior abdominal wall appears late in development. The embryologic study of the mesogastric area clarifies the real mechanism of development of the stomach and its lymphatic pathways with some differences from classic reports; these results agree with the more recent modification of the lymph nodes classification used in the radical treatment of gastric cancer.