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{Header}} Barry DT. and Donegan E. Malformation of the diaphragm in a dog. (1924) J Anat. 58: 266-267. PMID 17104018

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This 1924 paper by Barry and Donegan describes dog abnormal diaphragm development.

Modern Notes: dog | diaphragm

Historic Embryology - Respiratory
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Malformation of the Diaphragm in a Dog

By D. T. Barry, D.Sc., F.R.CS., and Evelyn Donegan, B.Sc.

Physiological Department, University College, Cork.

Ox opening the thorax of a pregnant bitch for the purpose of doing some experiments with the heart-lung preparation, we were at once struck by the abnormal appearance of things. The guiding finger behind the sternum met with no resistance such as is usually offered by the diaphragm after the xiphi- sternal cartilage is split. On completing the sternal cut the left lobe of the liver presented itself in the upper part of the left side of the thorax, and between it and the thoracic wall, as high as the level of the third rib, some coils of small intestine were seen; the heart was pushed to the right; there had been no occasion to palpate the apex-beat prior to opening. The pericardial sac was complete, and the heart rested in a pit on the upper surface of the liver, partly on the right lobe and partly on the left, without the intervention ofa diaphragm. It was held there by a short fold of pericardium attached to the anterior border of the diaphragm, behind, where the liver was also adherent. It was obvious at once that there was a defect in the diaphragm, which was then carefully examined.

The diaphragm presented a concave anterior border, for the most part free, but adherent to the liver behind the heart. The opening of the vena cava was about one inch behind this border, and the oesophageal opening about two inches behind it to the left of the vena cava (fig. 1). There was a large gap between this border and the front wall through which there was prolapse of a great part of the liver, the stomach and the small intestine into the thorax. The right lobe of the liver was adherent to portions of the anterior edge. This concave edge was limited on the left by attachment to the tenth costal cartilage and on the right to the ninth. The posterior portion of the diaphragm was perfectly formed and there was complete closure there.

The anterior tongue of the central tendon of the diaphragm ends in the pericardial fold. The central part of the diaphragm through which passes th oesophagus is thick and muscular; and while this is normal in the dog there is, however, an excess of muscle in this area; the vena cava opening is also surrounded by muscle but in thinner layers than the oesophageal. The chief tendinous parts are two lateral portions as seen in fig. 1. Blair describes many accessory muscle slips in the tendon of the human diaphragm (Journ. Anat. Lyi. Part 11, p. 214, 1923). In this animal’s diaphragm there certainly was abundance of muscle which looked like compensatory growth. The ribs and conformation of the thorax were normal.

The left lung was considerably pressed upon by the abdominal viscera; the edge of the liver compressing the vessels at the root and causing considerable congestion of the base and portions near the root. This lung weighed 85 gms. the right lung weighed 107 gms.

Fig. 1. Drawing of the upper surface of diaphragm.

Remarks: Evidently the malformation here affected that portion of the diaphragm which is developed from the septum transversum. The connective tissue which lies over this part in the embryo for some reason did not develop. The possibility of a traumatic injury to the diaphragm may, we think, be excluded, from the shape of the portion which was intact and its limitations. The parts formed from the mesentery, the pleuro-peritoneal membrane, were, as stated, perfect, and the gap corresponded exactly with that part derived from the septum transversum. The gastro-hepatic omentum with the foramen of Winslow were in their normal condition, though of course dragged to the left and upwards with the stomach.

The unusually large gravid uterus, containing five foetuses near term must have aggravated the condition, being probably the chief factor in the obstruction to the pulmonary circulation.

We have, unfortunately, no present opportunity of going extensively into the literature of this subject, but we consider the condition of sufficient interest to be reported.

Cite this page: Hill, M.A. (2024, April 18) Embryology Paper - Malformation of the diaphragm in a dog (1924). Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Paper_-_Malformation_of_the_diaphragm_in_a_dog_(1924)

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