Book - Handbook of Pathological Anatomy 2.12
|Embryology - 24 Jun 2021 Expand to Translate|
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- Ligaments: I. Trunk | II. Head | III. Extremities Muscles: I. Trunk | II. Head | III. Extremities Angiology: I. Heart | II. Body or Aorta Arteries | III. Body Veins| IV. Pulmonary Artery | V. Pulmonary Veins | VI. Lymphatic System | VII. A Comparison of Vascular System Nervous System: I. Central Nervous System
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Section V. Pulmonary Veins
§ 1635. The pulmonary veins (V. pulmonales , s. arteriœ venosœ) are usually destitute of valves, with some very rare exceptions.(l) They generally form on each side an upper and a lower trunk, which open at the four angles of the right auricle (§ 1308), and which, considered together, are a little smaller than the trunk of the pulmonary artery. The upper veins are a little larger than the lower, and are somewhat more distant from each other when they arrive at the auricle. Those of the same side are much nearer each other than those of the two sides. They are looser anteriorly than posteriorly, and are placed in front of the branches of the pulmonary artery and of the trachea. After proceeding a short distance, from four to six lines, each trunk, the inferior generally sooner than the superior, divides anew into at least two principal branches, viz. the upper into an upper and a lower branch, the lower into an anterior and a posterior branch, which commonly directly subdivide into two or more branches, before even penetrating into the fissure of the lung.
The right pulmonary veins are a little larger, but most generally much shorter than the left. They are always covered anteriorly by the descending vena-cava and also by the right auricle. The upper vein of this side comes from the upper and middle lobes of the right lung, from the first by its upper branch and by its lower branch from the second. The upper branch however usually receives one or more ramifications from the middle lobe, while the lower receives them only from the inferior lobe. The distribution of the pulmonary veins is then the opposite of that of the artery.
§ 1636. We not (infrequently find a greater(2) or less(3) number of trunks of the pulmonary veins, either from their division or their union. The first anomaly seems to be more common than the second. It does not always occur exactly in the same manner, and differs in quantity and quality. Most generally the number of trunks is increased by one only, there being five. In two cases now before us, the anomaly exists on the right side : the three trunks are situated one above another : the central trunk is much smaller than the other two, and is placed directly below the superior, being nearer to it than to the lower. We then observe in this only a greater development of the normal type.
(1) Kelch (Beytrœge zur path, anat., Berlin, 1813, p. 81, No. 59) has found, before the orifice of one of the right pulmonary veins, a valve, which is very curious, as a repetition of what occurs normally in several reptiles.
(2) Meckel, Mém. de Berlin, 1750, p. 167. — Haller, De part. corp. hum., f. i. f. ii. p. 123. — Portal, Mim. de Paris, 1771, Hist., p. 74. — Sandifort, Obs. anat. path., vol. iii. p. 41; vol. iv. p. 91.
(3) Loeseke, Obs. anat., Berlin, 1754, p, 26. — Portal, Mem.de Paris, loc. cit. — Haller, loc. cit. — Pohl, De vcnis, Leipsic, p. 1 1.— Sandifort, Obs. anat. path., book iii. p. 18.
Less commonly we find a third trunk, which we have observed also on the left side, and which, proportionally smaller than the usual supernumerary vessel, arises by branches coming from the posterior part of the upper and lower lobes, is separated from the right superior pulmonary vein by the right branch of the pulmonary artery, and empties from above downward and from behind forward, into the posterior part of the right portion of the pulmonary auricle, almost opposite its centre.
Still more rarely also the number of pulmonary veins is increased by two, and becomes six ; there are then sometimes three on each side, and sometimes four on one side and two on the other.(l) We regret that Sandifort did not state on which side the anomaly existed in the latter case.
The pulmonary veins seem to be diminished on the left side more frequently than on the right ; at least this diminution has been observed on this side by Loeseke, Sandifort, and ourselves, while the veins on the right side were normal.
Other anomalies of the pulmonary veins, such as the termination of all or of one only, in the descending vena-cava or in the right auricle, are much more rare.
Cite this page: Hill, M.A. (2021, June 24) Embryology Book - Handbook of Pathological Anatomy 2.12. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Book_-_Handbook_of_Pathological_Anatomy_2.12
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