Contribution to the topographical anatomy of the thorax in the foetus at term and the new-born child / by George S. Huntington.

  • Huntington, George S. (George Sumner), 1861-1927.
Date:
[1897?]
Catalogue details

Licence: Public Domain Mark

Credit: Contribution to the topographical anatomy of the thorax in the foetus at term and the new-born child / by George S. Huntington. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    It seems, therefore, more in accordance with the actual conditions to define the mediastinal surface as including that portion of the lung which is in relation with the mediastinal pleural reflection covering the vascular, glandular, visceral, and nervous structures of the mediastinal space. This area is separated by what we have termed the internal'''' margin from the surface in contact with the parietal pleura investing the walls of the thoracic cavity. This internal margin, varying in distinctness in differ- ent parts of its extent, is, therefore, the composite of the successive posterior borders of a series of impressions which result from the relation of this portion of the lung to the pleura investing the longitudinal vascular and visceral contents of the posterior part of the mediastinal space. The details of this margin will be subsequently considered. The surface of the lung in contact with the pleura covering the thoracic parietes is generally convex, and in the foetal lung is quite evidently divided into a lateral or sternocostal, and posteromedial or costovertebral surface. The sternocostal surface is limited anteriorly by the sharp anterior mar- gin, in which it meets the mediastinal surface. The posterior limit is afforded by a rounded but distinct border (Figs. V and VI, 6), which fits into the vertical groove formed by the succession of ribs and intercostal spaces at the point where the former change their original outward and backward direction to turn forward in conformity with the lateral curve of the thoracic wall. The costovertebral surface extends between this posterior border and the internal margin, as above defined. As the name proposed indicates, this surface comes into relation with the parietal pleura covering the lateral aspects of the vertebral centres and disks and the portions of the ribs and intercostal spaces which extend between the costovertebral line of articula- tion and the line indicated superficially by the succession of the costal angles. B. Changes in External Form During the Later Developmental Stages of the Lungs. In the earlier stages of development the posterior border is sharper, and the costovertebral surface is directed obliquely backward and inward (Figs. V and VI). As the lung develops, the increase in size affects pri- marily the posterior portions. Figs. VII to XII present the lateral and medial aspects and the out- lines of the basal surfaces of the right and left lungs of a foetus of thirty- one weeks (estimated). It will be noted (Figs. XI and XII, 6) that the posterior margin is more rounded, and that the costovertebral surface looks almost directly inwards (Figs. XI and XII, 5). This change in direction produces a diminution in the distinctness of the internal margin (Figs. XI and XII, 4) as seen from the basal surface, since the costovertebral surface forms a more direct continuation backwards of that part of the mediastinal surface which is in relation with the vertical structures occupying the posterior mediastinal space. At the same time it will be presently seen that the differentiation of the two surfaces, as indicated by the impressions pro- duced, becomes more marked with the full development of the lung.