Book - Handbook of Pathological Anatomy 2.14
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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 VII. A Comparison of the Different Regions of the Vascular System
§ 1706. According to a law established in our introduction, there is an analogy but not a perfect resemblance between the different parts of the vascular system, in respect to its three dimensions, that is, from right to left, from above downward, and from before backward.
§ 1707. In accordance with the same law, the most marked analogy is that between the right and the left half of the system, which differ but slightly. Except inconstant variations, the only one of consequence is that in the arrangement of the trunks given off to the head and the upper extremities by the arch of the aorta (§ 1335). This difference seems to be only a part of a general type, which exists in all the arterial system. At least, the right superior aortic intercostal artery and the bronchial artery of the same side usually arise by a common trunk (§ 1439), even as in anomalies, several vessels of the right side often unite in a single trunk, while on the left side one trunk divides into several. Thus, for instance, the left carotid artery not unfrequently arises from the innominata, although the left vertebral artery often comes from the aorta : so too the left renal artery divides into several trunks more frequently than the right. In the single instance we have seen of the high division of the brachial artery on one side only, this was the left. This side also is the only one where we once observed an uncommonly high division of the popliteal artery. The obturator artery arises from the crural artery on the left side more frequently than on the right. When the innominata is divided at the arch of the aorta into its two trunks, the right subclavian artery rarely remains on the right : it goes to the left, and arises more on the left of the aorta ; so that in fact this anomaly seems to depend primitively on an extraordinary development of the left side and to the predominance of its type over that of the right side ; this opinion is strongly favored by the fact that in cases of this nature the right subclavian artery no longer takes the shortest course to arrive at its limb, but turns aside, passing behind the esophagus.
(I) See our Handbuch der path. Anatomie, vol. ii. part 1, p. 183.
The special characters of the two extremities are often unusually developed simultaneously. Thus, for instance, the left carotid artery is a branch of the innominata, at the same time that the left vertebral artery arises directly from the aorta ; or the right and left carotid arteries are united in a single trunk, 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 common iliac veins are much longer than the synonymous trunks on the right side, and the superior and inferior thoracic canals of the left side unite, while the right superior proceeds alone.
Finally, the arrangement not unfrequently becomes unusually symmetrical, 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 analogies between them much exceed their differences.
The diaphragm separates the upper from the lower half of the vascular system. If we compare these two halves with each other, after leaving this muscular septum, we obtain the following results :
1st. In the chest, as in the abdomen, the large circulatory system comprises two, which are smaller, viz. the pulmonary circulation in the thorax and that of the vena portæ in the abdomen. The trunk of the vena portæ 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 portæ 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 conditions, which alone or united occur- in the system of the pulmonary vessels of most animals which have blood-vessels, and which are below the class of birds.
2d. 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 arteries 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 analogous to the lungs, whence the vessels of these organs are repetitions of those of the lungs in different degrees of perfection. The vascular system of the liver resembles that of the lungs, as it includes the different arteries of the system of the vena porta ; but it is less perfect. The renal and capsular vessels are still lower in the scale, for there we cannot trace the separation between the vessels of nutrition and those of secretion ; this separation is indicated in the kidneys by some vessels different from the renal arteries, which are distributed on the surface of these organs and in the renal capsules, by numerous vascular ramifications, which come from very different regions.
(/. The thymic arteries correspond to the spermatic arteries, as both generally arise from the trunk of the aorta, and the former frequently come from the bronchial arteries and the latter from the renal arteries.
e. The aortic intercostal arteries are represented by the lumbar arteries. In fact the latter are fewer ; but as the branches which arise from the middle sacral artery, a continuation of the trunk of the aorta, present the same arrangement as they, every difference in this respect disappears. The analogy remarked between the arteries which pass through the intervertebral foramina, above and below the diaphragm, is evidently strengthened by the fact that the superior intercostal artery is a branch of the subclavian (§ 1399), as the lateral sacral artery is one of the hypogastric artery.
f. The division of the upper and lower extremities of the aorta, and the arrangement of the vessels which arise from it on one side to go to the neck, the head, and the upper extremities, on the other to the organs of the pelvis and to the lower extremities, present a most striking analogy. The primitive iliac artery corresponds to the common trunk of the right subclavian and carotid arteries. It is true the analogy does not exist on the left side, but notwithstanding this difference is not essential, as it depends on a consecutive division, the analogy between the two regions is increased by the origin of the left vertebral artery directly from the arch of the aorta, between the left carotid and subclavian arteries, which is common, since this anomaly causes, in some measure, the union of the two vessels.
The carotid correspond to the hypogastric arteries, and the subclavian to the crural arteries, in respect to situation, origin, and distribution.
Of the trunks which arise from the carotid and the hypogastric arteries the superior thyroid and its branches correspond to the uterine and the vesical arteries, the facial and the ascending pharyngeal to the internal pudic and to its branches.
The differences in this respect are as follows :
The subclavian artery gives origin to the vertebral and the inferior thyroid artery ; the hypogastric to the gluteal and ischiatic artery. These latter are distributed like the branches of the subclavian and even of the axillary arteries. The former seem, at first view, to have none which correspond to them in the inferior vascular system, or to correspond to the vessels which arise from the hypogastric artery.
This difference almost disappears when the thing is examined attentively.
We cannot in fact deny that the vertebral and the inferior thyroid artery do not properly correspond to the hypogastric artery. The carotid arteries represent only a small part of the latter, which is much developed and reduced to a considerable trunk on account of the greater size of the parts it nourishes. The hypogastric artery is then divided in the upper part of the body into three trunks, the carotid, the vertebral, and the inferior thyroid artery. Hence why the inferior thyroid artery so often wholly or in great part arises from the carotid or the innominata artery, or is entirely deficient, or is replaced by the branches of the superior. The origin of most of the vessels of the neck and of the upper region of the shoulder from the inferior thyroid artery also favors this analogy very much, as these vessels are very similar to the gluteal, the ischiatic, and the obturator arteries.
The vertebral artery is ranked as a distinct trunk because of the size of the brain and the spinal marrow, organs to which it carries blood ; but it evidently corresponds in its mode of distribution, to the lateral sacral arteries furnished by the hypogastric artery.
Many vessels which correspond in their distribution, arise above from the subclavian, and below from the hypogastric artery.
The branches which arise directly from the subclavian and from the crural artery are very analogous. The internal mammary artery exactly resembles the epigastric artery, as the first proceeds on the sides of the posterior face of the sternum, and the second backward and on the sides of the linea alba which corresponds to this bone. The anterior intercostal arteries, given off by the internal mammary artery, are represented by the analogous branches of the epigastric artery.
The circumflex iliac artery seems to us to correspond exactly to the long external thoracic artery (§ 1405 ).
The external pudic arteries manifestly represent several external thoracic arteries.
In both extremities the trunk of the artery divides a short distance above the first articulation into a superficial vessel, which descends to the extremity of the limb, and into a deep vessel, which does not extend beyond the first articulation, that is, beyond the arm or the thigh.
The two circumflex arteries arise very high, sometimes from the superficial and sometimes from the deep trunk. They evidently correspond in their relations with the bone and the first articulation of the extremity, although they slightly differ in their distribution, as those of the arm are expanded in the superficial, and the femoral in the deep muscles, and also as one of the circumflex arteries of the arm is generally much smaller than its corresponding one in the thigh. This latter circumstance depends upon the greater development of the muscles of the thigh. The first depends upon the fact that the highest branches, arising from the hypogastric artery, are distributed to the muscles corresponding to those of the arm, which receive the blood from the circumflex arteries.
The superficial brachial artery divides like the crural, at the second articulation, into two trunks, one of which soon bifurcates in a similar manner. The anterior tibial corresponds to the radial artery, the posterior to the ulnar, and the peroneal to the interosseous artery.
The division of these vessel's however differs remarkably, as it frequently occurs unusually high in the upper extremity, while this anomaly is very rare in the lower extremity, as is proved by our numerous observations and those of other anatomists.
It is difficult to assign the cause of this difference. The most probable explanation is that it depends upon the fact that the upper limbs form and are developed sooner than the lower, and are nearer the hear , Perhaps it depends partly on the greater length of the fingers, the volume of which, compared to that of the posterior part of the hand, much exceeds that of the toes, compared with the posterior part of the foot, and hence they always appear long before the latter. This anomaly, which is almost peculiar to the arteries of the upper extremities, would consequently arise from the normal arrangement of these latter ; to support which conjecture, we would mention the analogous difference in the arrangements of the muscles of the fingers and toes, since the hand presents no trace of the short flexor and extensor of these appendages of the foot. We even recognize with a little attention, that all the upper part of the vascular system differs thus from the lower ; for the separation of the carotid with the vertebral and inferior thyroid arteries, the constant separation of the carotid with the subclavian artery on the left side, the frequent origin of the vertebral artery with the latter, and the not unfrequent existence of a second inferior thyroid artery, (§ 1395 ) are analogous phenomena, of which we find no trace in the lower extremities.
Thus the vascular system of the upper part of the body is characterized by a tendency to divide. But it is not the only part where this tendency is remarked, since it is observed in the development of the brain, the multiplication of the organs of the senses, and the perfection of the extremities, which are perhaps the cause and condition of it.
The arteries of the lower extremities have entirely opposite characters. The circumflex arteries of the thigh are given off by the deep crural artery, more frequently than those of the arm are by the deep brachiaL The superficial crural artery seldom divides higher than usual, and the number of branches given off by the popliteal artery, is frequently less, because the peroneal or the anterior tibial, the first much more frequently and to a greater degree than the second, ceases to form a distinct trunk, and is replaced by the branches of the other vessels of the leg, precisely as the fibufa is in some measure only an appendage of the tibia, while in the fore-arm the radius and ulna are also developed, and both articulate with the humerus, and exactly also as the toes are developed much more imperfectly, and much less movably than the fingers.
The articular arteries of the elbow and of the knee differ principally,
1st. Because the upper vessels of the thoracic extremity axise higher, and are always separated from the others, while those of the pelvic extremity are situated lower, and usually arise by a common trunk.
2d. Because the inferior arteries of the pectoral limbs aiise from the arteries of the fore-arm, and those of the abdominal members from the lower part of the popliteal artery. The internal and superior popliteal artery not unfrequently arises very high ; there are always two smaller inferior articular popliteal arteries which arise from the anterior and posterior tibial arteries, and not very unfrequently the recurrent radial artery is given off by tire brachial artei'y. When the popliteal artery divides a little higher than usual, its two branches furnish also the two largest inferior articular arteries of the knee.
Mairy anatomists mention as a difference in the distribution of the arteries of the hand and foot, the want of a superficial arch in the latter. We have never found this assertioxr to be connect, and it certainly depends upon a want of cai’e in searching into the analogies. In fact the internal plantar artery doubtless corresponds in its origin and course to the superficial palmar branch of the ulnar artery. Besides we have always known it to anastomose with the plantar branch of the anterior tibial artery, so as to form a superficial plantar arch.
But there is a real difference between the origin of the arteries of the fingers and toes, inasmuch as the former arise from the superficial, and the latter from the deep arch. This deviatioxr of the vessels on the surface of the sole of the foot, is sometimes developed to such an extent, that the arteries of the toes come from the superior rather than from the inferior perforating arteries (§ 1530). This arrangement appears to be intended to prevent the compression of the ai’teries of the toes by the weight of the body. Perhaps also it depends on the difference between the back and the palm of the hand, as also between the back and the sole of the foot, in regard to muscularity ; and perhaps the development, on the back of the foot, of the muscles which do not exist on that of the hand, is the reason that the arteries of the toes aiise more deeply. Finally, this difference sometimes disappears, since in some subjects the arteries of the fingers are given off by the superficial palmar arch.
3d. The veins of the upper and lower portion are perhaps more similar than the arteries, at least the arteries present a difference which does not exist in the arrangement of the left jugular and subclavian veins, and that of the left primitive iliac vein.
4th. The upper and lower portions of the lymphatic system, also present the same analogies in respect to the existence, the number, and the situ ation of the vessels and of the glands.
§ 1709. In the vascular system as in the rest of the organism, the analogy is not so great forward and backward, as from right to left, and from above downward. We may, however, in this direction, compare the internal mammary and the epigastric arteries to the aorta, and its branches to the posterior intercostal and the lumbar arteries. So, too, there is a correspondence between the anterior and the posterior branches of the anterior and posterior intercostal arteries and of the lumbar arteries : perhaps in the neck and in the head, between the superficial and the deep arteries, certainly in these two regions, and in the spinal marrow, between the anterior and the posterior spinal, and also between the occipital and the frontal arteries; finally in the limbs between the anterior and posterior circumflex arteries of the humerus, the external and internal circumflex arteries of the femur, the superficial and the deep brachial and the crural arteries, the radial and the ulnar, and the anterior and the posterior tibial arteries, the dorsal arches of the back of the hand and of the foot, and the superior interosseous arteries of the plantar and palmar arches.
The venous system presents the same analogies, which are rendered still more striking by the existence of an azygos and of a semi-azygos vein, which correspond very evidently to the internal mammary veins.
We may compare with the large thoracic canal, which proceeds before the vertebral column, a second lymphatic duct, which ascends behind the sternum.
Cite this page: Hill, M.A. (2020, September 18) Embryology Book - Handbook of Pathological Anatomy 2.14. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Book_-_Handbook_of_Pathological_Anatomy_2.14
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