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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    left in situ in the posterior part of the mediastinum after removal of the right lung explains this appearance (Figs. XXVIII, XXX). The azygos vein, ascending in the mediastinum, occupies in main a nearly medial position, only beginning to deviate markedly to the right on reach- ing the level of the sixth thoracic vertebra. Above this point the vein comes into close contact with the right mediastinal pleura and impresses the mediastinal surface of the lung behind the hilus, as indicated. Below this point the vein gradually recedes from the mediastinal pleura, and, on reflecting the membrane, the right lateral margin of the oesophagus begins to appear between the posterior margin of the hilus and vein. This oesophageal area begins above as a narrow pointed surface which expands in descending, until in its lower portion it equals the inferior vena cava in sagittal measure. With the parts undisturbed and in their natural condi- tion, the gradual recession of the azygos vein from contact with the right mediastinal pleura, and its replacement in relation to the membrane by the right border of the oesophagus, is affected without producing any abrupt line of demarcation. Consequently, in the hardened lung removed from the thorax, the azygos groove, sharp and well defined above, gradu- ally fades out below the middle of the hilus, and is replaced by the broader, smooth surface in contact with the mediastinal pleura investing the oesoph- agus (Figs. XX, XXII, XXIII, 7). The entire region of the mediastinal lung surface dorsal to the hilus is, therefore, composed of an upper narrower and lower wider oesophageal area, separated from each other by the surface in contact with the azygos vein. The latter structure is rendered prominent in the upper mediastinal region by its course upward, forward, and to the right, and by the under- lying oesophagus. Below the middle of the hilus, on the other hand, the vein gradually recedes from the mediastinal pleura and lies nearer the median line, being enabled to assume this position by passing behind the oesophagus, the latter tube gradually inclining forward, and ceasing its close apposition to the anterior surface of the vertebral column. The relative extent of these areas of relation of the mediastinal lung surface with the contents of the mediastinum is shown schematically in Fig. XXIIa. 3. Topography of Mediastinal Contents. Left Side. Fig. XXYI shows the mediastinal contents in situ covered by the pleura in a foetus at term (D), and Fig. XXVII shows the same structures removed from the thorax, with the pleura partially reflected, in the infant immediately after birth (F). In front, as on the right side, the lateral surface of the thymus gland (XXVI, 5, XXVII, 4) appears above, the prominent pericardium (XXVI, 7) below, the latter crossed obliquely by the left phrenic nerve (XXVI, 6, XXVII, 5). At the upper and posterior margin of the left pulmonary root, the arch of the aorta produces a marked elevation of the mediastinal pleura, which is continued along the entire posterior border of the medias- tinum by the thoracic aorta, the elevation becoming gradually less marked as the vessel approaches the diaphragm (XXVI, 15, XXVII, 16).