ISRAEL JOURNAL OF
VETERINARY MEDICINE
Vol. 56 (1)) 2000
COMPARATIVE MACROANATOMIC INVESTIGATIONS OF THE
VENOUS DRAINAGE OF THE HEART IN AKKARAMAN SHEEP AND
ANGORA GOATS
K. Besoluk and S. T¦p¦rdamaz
Department of Anatomy, Faculty of Veterinary Medicine, Universty of Sel‫ח‬uk 42031
Konya / Turkey
Abstract
This study was carried out to evaluate the origins, course and termination of the cardiac veins in
Akkaraman sheep and Angora goats. The vessels are the great coronary vein, middle cardiac vein, right
cardiac vein and smallest cardiac vein. Latex was injected into the jugular vein of eight adult healthy
Akkaraman sheep and Angora goats. The veins were dissected, and it was shown that the middle
cardiac vein and the great coronary vein coursed with the branches of the coronary arteries with which
they anastomosed.
Venous blood from the great coronary vein and the middle cardiac vein emptied into the right atrium
via the coronary sinus. The venous blood from the interventricular septum was conveyed to the middle
cardiac and great coronary vein.
Introduction
The coronary sinus, situated on the atrial surface of the heart received the left azygos vein which
opens into the right atria (1-4). It receives venous blood from the great coronary vein, the left marginal
vein and the left azygos vein (5). According to Hegazi (6), the coronary sinus in sheep receives the
great coronary vein, the left marginal vein and the left azygos vein but in goats, it takes in addition the
middle cardiac vein. The coronary sinus is 2.5 and 2.8 centimetres long in sheep and goat respectively.
The middle cardiac vein receives blood from the atrial surface and the area is supplied by the
subsinuosal interventricular branch. It ascends in the paraconal interventricular groove along with the
paraconal interventricular branch of the left coronary artery (6,7) and terminates at the coronary sinus
(8). According to May (9) and Hassa (10) the middle cardiac vein opens into the right atrium on the
cranial surface of the coronary sinus. At the apex of the heart, this vessel anastomoses with the great
coronary vein (6) or branches of the left marginal vein (5).
The great coronary vein originates from the incisura apicis cordis and anastomoses branches of the
middle cardiac vein (6,9). It continues to the apex of the heart as the paraconal interventricular branch
in the paraconal interventricular groove in sheep. In the coronary groove, it accompanies the
circumflex branch of the left coronary artery (5,6,7,9). The vessel courses in the adipose tissue covered
by the left auricula and terminates at the adjoining point of the left azygos vein with the coronary sinus
(9,10).
The left marginal vein originates from the near part of the apex of the left ventricle and continues
towards the basis of the heart along the caudal border of the heart. When the vessel reaches the
coronary groove it crosses the circumflex branch of the left coronary artery and opens into the coronary
sinus at the level of the left azygos vein and coronary sinus junction (5). According to Hegazi the
vessel opens into the coronary sinus in sheep, while it joins the great coronary vein in the goat (6).
The right cardiac vein, directly opens into the right atria (6). These small vessels draining the venous
blood from the right atria and the right ventricle reach the coronary sinus, after following a short course
in the coronary sinus (8).
The smallest cardiac veins are four or five in number (9) and are 3-5 mm. long (6). They carry venous
blood from the myocard into the chambers of the heart (5,7).In general, they terminate between the
pectinati muscles of the right atria (6,9).
Materials and Methods
Eight adult healthy Akkaraman sheep and Angora goats of both sexes, 3-6 years old and weighing 2530 kg were used in this study. Animals were anaesthetized with xylazin (Rompun, Bayer), (1.5 mg/kg)
and cyclohexanol (Ketalar, Parke-Davis), (10 mg/kg).
The blood of the anaesthetized animals was withdrawn from the common carotid artery. Plastic
catheters were inserted into both the jugular vein and caudal vena cava which were catheterized at the
caudal part of the liver by laparotomy. The vessels were washed with 0.9 % physiological saline.
Stained latex which was prepared by mixing 120 ml of latex with 6 ml of textile stain (Deka
permanent 20/20, blue textile dye) was injected to the vessels. After 12 hours at room temperature, the
thorax was opened and drainage of the heart was observed either macroscopically or with a dissecting
microscope (Nikon SMZ-2T) and photographed. Nomina Anatomica Veterinaria terminology was used
(11).
Results
The coronary sinus (Fig. 1/D) was the continuation of the left azygos vein and opened into the right
atrium ventral to the opening of the caudal vena cava in Akkaraman sheep and Angora goats. The heart
was drained by a number of veins. It was seen that the veins of the heart were alongside the coronary
arteries, and that the coronary sinus received the middle cardiac, great coronary, small cardiac, veins.
The left marginal vein (r. intermedius, v. cordis caudalis) (Fig. 1/B, 3/B) originated at the apex
of the heart and coursed to the basis of the heart on the left ventricular border to receive small branches
from atrial and auricular surface of heart in sheep. It received left distal ventricular branch at the
proximal third on the left ventricular border. At this level, it anastomosed with a branch of the
subsinuosal interventricular branch and then reached the coronary groove curving to join the coronary
sinus. This vessel originated as many small branches at the auricular surface of the apex of the heart in
the goat. It then anastomosed with a branch of the distal collateral branch of the paraconal
interventricular branch at the distal third of the left ventricle and to the ventral surface of the circumflex
branch without a curve.
The right cardiac vein (Fig. 4/A) originated from the right ventricle and coursed cranially 0.5 cm.
after origin, it crossed dorsally the right coronary artery and received two branches, one from the right
atria and the other from the right ventricle. It coursed cranially in the coronary groove at the level of
the right ventricle border. The following branches contributed to the formation of the right cardiac
vein: The right proximal atrial vein (Fig. 4/C) was formed by small branches originated from the
coronary groove near the right atria. Vena coni arteriosi (Fig. 4/E) originated as small two branches at
the proximal third of the right ventricle 2 cm ventral to the conus arteriosus. These branches joined
each other and took the right proximal ventricular vein at the ventral border of the right auricle.
The smallest cardiac vein (Fig. 5/A) was 2-3 mm. channels which originated in the right atrial
myocardium and opened directly into its chambers. These vessels generally occupied in spaces
between the pectinati muscles of the right auricle, they were rarely seen at the level of the right
ventricle border. The smallest cardiac vein was not observed at the left atria and ventricle in sheep,
although they were seen at the left atria in the goats.
FIGURES:
Figure 2. The veins of the heart in Akkaraman sheep (auricular
Figure 1. The veins of the heart in Angora
surface)
Goat (caudal view)
Figure 3. The veins of the heart in Angora Goat (auricular surface)
a. aorta b. the left auricle c. the cranial vena cavae d. the caudal
vena cavae e. the pulmonary trunk f. the left azygos vein
A. the middle coronary sinus
B. the left marginal vein
C. the great coronary nein
D. the coronary sinus
E. the paraconal interventricular branch
F. v. coni arteriosi
G. the distal collateral vein H. the proximal collateral vein
Figure 5. The smallest cardiac vein in Akkaraman
a. the right ventricle
b. the wall of the right ventricle
Figure 4. The right cardiac vein in Akkaraman sheep
A. the smallest cardiac vein
a. aorta b. the right auricle c. the cranical vena cavae d. the
pulmonary trunk e. the left azygos vein
A. the right cardic vein
B. the right distal ventricular vein
C. the right proximal atrial vein
D. the right proximal ventricular vein
E. v. coni arteriosi
Discussion
In contrast to previous reports (5), the branches from the wall of the pulmonary veins opened into
the coronary sinus in Akkaraman sheep and Angora goats. In addition, the coronary sinus received the
branch from the wall of the right atrium in Angora goats.
Although Hegazi stated that the middle cardiac vein joined the right atria (6), we found that the
middle cardiac vein ended in the coronary sinus in both species. Dursun (8) has reported that this vessel
joined the coronary sinus. May (9) and Hassa (10) assumed that this vessel opened cranially to the right
atria. We found that the middle cardiac vein coursed under the myocardial bridges at the distal half of
the subsinuosal interventricular groove and terminated at the coronary sinus in sheep and goats.
Nickel (5) has reported that the left marginal vein terminated to the coronary sinus in ruminants and
Hegazi (6) assumed that this vein opened into the coronary sinus in sheep and ended at the great
coronary vein in the goat. In our study, the left marginal vein emptied at the coronary sinus in sheep
and the at great coronary vein in goats.
Hegazi (6) stated that the great coronary vein anastomosed with the middle cardiac vein at the level
of the incisura apicis and apex of the heart. We found identical results with those of Hegazi. In this
study and according to others, it was observed that the paraconal interventricular branch received
branches from the right and left ventricles in both species.
Hegazi stated that the right cardiac vein drained the right half of the heart and emptied in the right
atrium (6). Nickel has reported that the right cardiac vein emptied in the coronary sinus (5). In our
study, it was observed that v. coni arteriosi, right proximal ventricular vein (Fig. 4/D) and right
proximal atrial vein joined the right cardiac vein.
The smallest cardiac vein numbered four (5) and was found in spaces between the pectinate
muscles (6,9). Our results of the smallest cardiac vein corresponded to previous observations (5,6,9).
There is some discussion concerning the presence of the smallest cardiac vein in the left ventricle.
While Nickel has reported that these veins could be observed in the left atrium (5), we didn’t find that
the smallest cardiac vein in the left atrium in sheep or goats. cardiac vein in the left ventricle. While
Nickel has reported that these veins could be observed in the left atrium (5), we didn’t find that the
smallest cardiac vein in the left atrium in sheep or goats.
References
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