Talk:Paper - A model demonstrating the changes in position and peritoneal relations of abdominal viscera during development (1912)

A Model Demonstrating The Changes In Position And Peritoneal Relations Of Abdoiniinal Viscera During Development

Henry Bayon

From the Department of Anatomy, The Tulane University of Louisiana

Thhee Figures

Differences in position of the abdominal viscera and in their peritoneal relations at various stages of development occupy the front rank of difficulties which confront the teacher of anatomy. Text-books are lavish in detail, and clearness of description is not lacking in either text or atlas. The fact remains, nevertheless, that but few students obtain a clear idea of the successive changes which occur in the abdominal cavity during growth from the simple arrangement of the gastro-intestinal canal and its common mesentery in the early foetus to the complicated conditions acquired at term.

Huntington meets the difficulty by comparing the dissection of the human abdomen with that of the cat, and a better illustration cannot be found to substantiate the value of comparative anatomy in the study of the development of human organs. Huntington's method consists in directing the student to make comparisons between the abdominal viscera of the cat and those of the human subject. Advantage is taken of the fact that the peritoneal arrangement of the adult cat is much like that of the human foetus in early development. By a series of manipulations of the viscera of the cat, those movements and displacements of the organs, which occur later in the foetus and which result in the permanent fixation of peritoneal relations, may be imitated.

Suggested bj' Huntington's method, a model is herewith presented which has been found to simplify to our students, the

439

440

HENRY BAYON

explanation of processes by which the adult conditions in the human are attained. An apology for crudeness of the model should be offered. In its favor is the simplicity of its construction which is suggestive of simplicity rather than complexity in developmental processes. By manipulations of the organs represented, one may easily demonstrate the movements in rotation of

Caecum J

Fig. 1. Model representing gastro-intestinal canal before rotation of stomach and intestine.

the stomach and in torsion of the mesentery upon which the various changes in subsequent peritoneal relations essentially depend. A board about 2 feet long and 7 inches wide (fig. 1) represents the posterior abdominal wall and a piece of muslin covering it represents the foetal parietal peritoneum. To the mid-line of the

MODEL SHOWING PERITONEAL DEVELOPMENT

441

boiird is attaclunl ti doublo hiyor of muslin, the comiuou mesentery. In the upper part of this, the mesogastrium, are enclosed the stomach, pancreas and sjiloen, and its lower part is made up to represent the mesentry proi)er, which encloses the primitive intestinal loop with some development of intestinal coils in the uppjer

Caecum

Descending Colon

Fig. 2. Model showing change in relations of viscera attending rotation of stomach; figure shows also first step in twisting of the mesentery at the duodenocolic isthmus.

limb of the loop and the caecum and the colon in the lower limb. The stomach, pancreas, spleen and kidneys are represented by cotton cushions and the intestinal canal by a soft cotton rope. The duodeno-colic isthmus is shown with the superior mesenteric vessels passing to the intestine.

442

HENRY BAYON

The formation of the bursa omentahs and foramen of Winslow is illustrated by rotating the stomach from the sagittal to the transverse plane and by folding the mesogastrium (fig. 2). The ventral part of the fold then corresponds to the gastro-splenic omentum, the dorsal part of it to the posterior ligament of the spleen, and incidentally the displacement of the vagi nerves from the sides of the oesophagus to its ventral and dorsal surfaces is

Hidnuj

Svp'r avoJeno^ Jeiono/l fold

ksctnJiKCj Colon

Spleen

Siomtuk

fancreas Iluodtnum Itif'r JuoJtu.O' Jc-wna-l fold

DeicenJiM Colon.

CaecuM

Fig. 3. Model shows position of abdominal viscera after rotation of stomach and complete twisting of mesentery.

demonstrated. • Rotation of the stomach is accompanied by rotation of the pancreas and duodenum which latter are thus made to leave their sagittal position for the transverse. The movement of twisting of the mesentery is next performed: the small intestine is made to sweep from right to left below the large intestine, the caecum is carried up from left to right and above the small intes

MODEL SIIOWIXC PERITONEAL DKVKF.OI'MENT 443

tiue as in tiguiv 2, and in its travel, the ascending meso-colon is made to pa^s over the duodenum and pancreas which have rotated with the stomacli and have been made to he in the transverse phxne. .Vfter this twisting of the mesentery on the duoder.ocohc isthmus has been understood, it is quite easy to explain how the ascending meso-colon, pressed backwards by the developing convolutions of the small intestine, eventually becomes a parietal layer, and how the pancreas and duodenum, which have been caught behind the ascending meso-colon, lose their embryonic peritoneal covering and appear to have developed in a postperitoneal position (fig. 3). The jejunum is now seen emerging from behind the newly acquired parietal peritoneum and at the duodeno-jejunal angle, the superior and inferior duodeno-jejunal folds and fossae (fig. 3) may be imitated by the twisting of the mesentery.

The peritoneal and non-peritoneal areas of the kidneys are made clear and the occasional persistence of the descending mesocolon, in contrast to the more constant disappearance of the ascending meso-colon, is explained by the more extensive travel of the caecum and ascending colon, in comparison with the relatively stationary position of the descending colon.

Finally after the disappearance of the ascending meso-colon has been demonstrated, the new line of attachment of the root of the mesentery proper explains itself.

444 BOOKS RECEIVED

BOOKS RECEIVED

The receipt of publications that may be sent to any of the five biological journals published by The VVistar Institute will be acknowledged under this heading. Short reviews of books that are of special interest to a large number of biologists will be published in this journal from time to time.

BRAIN AND SPINAL CORD, A manual for the study of the morphology and fibre-tracts of the central nervous system, Dr. Med. Emil Villiger, privatdozent in neurology and neuropathology in the University of Basel, translated by George A. Piersol, professor of anatomy in the University of Pennsylvania, from the thii-d German edition, with 232 illustrations (43 in colors), 290 pages including index and bibliography, 1912, $4.00. J. B. Lippincott Company, Philadelphia and London.'

This is an excellent translation of the German text (reviewed in The Anatomical Record, volume 5, number 4, pages 195 and 196, 1911) making this useful manual accessible to American students, to whom it is heartily recommended.

A CLINICAL MANUAL OF THE MALFORMATIONS AND CONGENITAL DISEASES OF THE FCETUS, Professor Dr. R. Birnbaum, chief physician to the university clinic for women at Gottingen, translat<>d and annotated by G. Blacker, M.D., 58 illustrations and 8 plates, 380 pages, 1912. P. Blakiston's Son and Company, Philadelphia.

MANUAL OF HIBIAN EMBRYOLOGY, written by Charles R. Bardeen, Madison, Wis.; Herbert M. Evans, Baltimore, Md.; Walter Felix, Zurich; Otto Grosser, Prague; Franz Keibel, Freiburg, i.Br.; Frederic T. Lewis, Boston, Mass.; Warren H. Lewis, Baltimore Md.; J. Playfair McMurrich, Toronto; Franklin P. Mall, Baltimore, Md.; Charles S. Minot, Boston, Mass.; Felix Pinkus, Berlin; Florence R. Sabin, Baltimore, Md.; George L. Streeter, Ann Arbor, Mich.; Julius Tandler, Vienna; Emil Zuckerkandl, Vienna; edited by Franz Keibel, Professor in the University of Freiburg, i.Br. and Franklin P. Mall, Professor of Anatomy in the Johns Hopkins University, Baltimore, U.S.A., in two vohimes, volume 2, with 658 illustrations, many of them in colors, 1032 pages including index, 1912. Volume 1 was published in 1911. The volumes are not sold separately, $20.00 for the set. J. B. Lippincott Company, Philadelphia and London. ,