Volume 1

Manual of descriptive and pathological anatomy ... / Translated from the German into French, with additions and notes, by A.J.L. Jourdan ... and G. Breschet ... Translated from the French, with notes, by A.S. Doane, and others.

  • Meckel, J. F. (Johann Friedrich), 1781-1833
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: Manual of descriptive and pathological anatomy ... / Translated from the German into French, with additions and notes, by A.J.L. Jourdan ... and G. Breschet ... Translated from the French, with notes, by A.S. Doane, and others. Source: Wellcome Collection.

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    primitively on an extraordinary development of the left side and to the predorninance of its type over that of the right side ; this opinion is strongly favoured by the fact that in cases of this nature the rightsuh- elavian artery no longer takes the shortest course to arrive at its liinb, but turns aside, passing behind the esophagus. The special characters of the two extremities are often unusually developed simultaneously. Thus, for instance, the left carotid artery is a brauch of the innominata, at the same time that the left vertebral artery arises directly from the aorta ; on the right and left carotid arteries are united in a single trank, when the right subclavian artery arises below the left. The contrary seems to be the case with the venous and lymphatic Systems; for the left subclavian and commou iliac veins are much longer thau the synonymous trunks on the right side, and the Supe- rior and inferior thoracic canals of the left side unite, while the right Superior proceeds alone. Finally, the arrangement not unfrequently becomes unusually sym- metrical, either by the Union or the divisions of the trunks, or because a trunk which is generally placed on the right or the left proceeds on the median line. § 1708. Although the upper and the lower halves of the vascular System are less similar than the right and the left, the aualogies between them much exceed their differences. The diaphragm separates the upper from the lower half of the vas- cular System. If we corapare these two halves with each other, after leaving this muscular septum, we obtain the following results : Ist. In the ehest, as in the abdomen, the large circulatery system comprises two, which are smaller, viz. the pulmonary circulation in the thorax and that of the vena portse in the abdomen. The trunk of the vena portse is an imperfect repetition of the right half of the heart: its arterial portion represents the pulmonary arteries, and the hepatic veins correspond to the pulmonary veins. The System of the vena portse is a very imperfect imitation of the pulmonary System, because no muscular heart is there developed, and because the veins open into the general venous System. These are however two condi- tions, which alone or united occur in the System of the pulmonary vessels of most animals which have blood-vessels, and which are below the dass of birds. 2nd. The upper and the lower halves of the arterial System are repetitions of each other in the following respects : a. The superior and inferior diaphragmatic arteries correspond. b. The esophageal arteries, the celiac, and the two mesenteric arte- ries correspond by large anastomoses. c. The bronchial arteries are represented by a part of the renal and capsular arteries, and by the hepatic. In fact we may consider the liver, the renal capsules, and the kidneys, as analogons to the lungs, whcnce the vessels of these Organs are repetitions of those of the lungs in different degrees of perfection. lhe vascular System of tue liver