A CORRELATIVE STUDY OF THE ANATOMY OF THE 
CARDIOVASCULAR SYSTEMS OF ANIMALS AND MAN 
Wesley D. Anderson* 
Aspects of the gross and microscopic anatomy of the 
cardiovascular systems and associated structures of the 
dog, sheep, calf and pig were correlated with man. They 
were: (1) heart, great vessels of the thorax, bronchial 
arteries, azygos venous systems and arterial supply to 
the spinal cord; (2) intracranial arterial systems and 
venous drainage of the head and neck; (3) arterial 
supply to the ruminant stomach; and (4) arterial 
patterns to the extremities. The mediastina, pericardium 
and its sinuses, and valvules and cusps of the heart 
were similar in sheep, calf and man while the azygos 
systems, ascending aorta, aortic arch and the course and 
termination of the coronary arteries differed. The 
vertebralbasilar system was similar in all four species 
but the internal carotid system and venous drainage of 
the head and neck differed markedly in the animals and 
from man. The arterial supply to the ruminant stomach 
was from a celiac-cranial mesenteric trunk or from the 
celiac artery. The rumen received its entire arterial 
supply from the right and left ruminal arteries and 
blood supply to the abomasum (true stomach) was from 
the common hepatic and left gastric arteries. The 
anatomy of the arterial patterns of limbs of dog and 
calf was studied with a view to employing them for the 
study of collateral circulation to the distal limb in the 
event of proximal ligation or thrombosis. When both 
femoral arteries were ligated below the origin of the 
profunda femoris in ten dogs, there was no noticeable 
effect on limb function nor gross evidence of ischemia or 
necrosis in the distal limb because of the extensive an- 
astomoses between branches of the profunda femoris, 
internal iliac and femoral arteries. 
INTRODUCTION** 
The knowledge of how organs and tissues of 
animals compare anatomically to those of man 
1 is becoming increasingly important today. The 
selection of experimental animal models is often 
based in part on the similarity in gross or 
histological structure between animal and man. 
[ Unfortunately the animal body has not been 
studied anatomically in as great a detail as the 
human body. 
J *Department of Anatomy, University of Minnesota Medical School 
ft Minneapolis, Minnesota 55455. 
** University of Minnesota PH43-68-1377 Vascular Anatomy of 
the sheep. 
The objective of this study is to describe por- 
tions of the cardiovascular system in sheep and 
other quadrupeds and relate these findings to 
comparable structures in man. The use of the 
two ruminant species, the sheep and calf in 
cardiovascular research is becoming increas- 
ingly common; therefore, emphasis in this pa- 
per will be placed on these two species. Also a 
knowledge of how the anatomy of these species 
relates to man is relevant to the eventual goal 
of cardiovascular research today, namely the 
application of new knowledge gained from ani- 
mal experimentation to improve the health and 
well being of human beings. Directional nomen- 
clature used has been based upon the anatomical 
position for quadruped mammals which is the 
erect position in which the animal is standing 
firmly on thoracic and pelvic limbs with head 
directed forward. In most cases the terminology 
of the Nomina Anatomica Veterinaria of 1968 
used in this study is based upon the anatomical 
position ; however in some cases, as in the case 
of the coronary arteries, it is not. Plastic cast 
injections of the cardiovascular system of sheep 
and other species have documented the course 
of these and other vessels and thus have been 
of value in establishing nomenclature for this 
paper which is comparable to the well accepted 
NA terminology for human beings. In some 
cases the older anatomical term has been in- 
cluded in parenthesis and in several cases the 
comparable human term has likewise been 
parenthesized. 
THORAX 
Thoracic Inlet 
The bony thorax of many quadrupeds is tri- 
angular in shape. In the case of the sheep (Fig- 
ure 1), it has a narrow spax, the cranial tho- 
racic aperature, and a base more than six 
times as wide called the caudal thoracic apera- 
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