Anatomical study of a left single coronary artery with special reference to the various distribution patterns of bilateral coronary arteries

A left single coronary artery of heart was observed during anatomy practice at Kumamoto University School of Medicine in a 73-year-old female cadaver who died from a thalamic hemorrhage. The left single coronary artery, having a single orifice in the left aortic sinus, bifurcated into the anterior interventricular (IVa) and circumflex (CIR) arteries. No orifice of the right coronary artery was found on the aortic wall. Giving off a branch which traversed the upper part of the infundibulum to supply the anterior upper region of the right ventricle, the IVa descended in the anterior interventricular sulcus to supply the apex of the heart. The CIR curved leftwards in the atrioventricular sulcus to reach the posterior surface, after which it continued to emerge again into the anterior surface. The atrial arteries showed no anomalous distribution pattern and histological observation revealed no pathological abnormality other than a slightly thickened tunica intima. Furthermore, we observed the distribution patterns of bilateral coronary arteries in 377 hearts dissected during anatomical practice over 13 years at Kanazawa University (1980–1986) and Kumamoto University (1993–1998). Although the reason why only the right coronary artery was absent is left unexplained, it was concluded that the left single coronary artery in this study, having the developed left conal and circumflex branches, was an extreme case of the left dominant series of coronary arteries. The formation of single coronary arteries can be explained embryologically by the change of flow in the capillary plexus established on the ventricle wall.     

The coronary vessels in the heart of a marsupial,Trichosurus vulpecula

The coronary arteries and veins are described in the phalanger (Trichosurus vulpecula), an Australian marsupial, after study of 16 hearts. Several hearts were prepared by injection of the vessels with either latex or vinyl plastic. The distributing branches of both coronary arteries are within the myocardium and are not visible on the surface of the heart. The right coronary artery arises in typical fashion and supplies the non-septal wall of the right ventricle almost entirely, the dorsal half of the interventricular septum, the dorsal part of the non-septal wall of the left ventricle and part of the right artium and its ventral auricle. The left coronary artery also arises typically and supplies the greater part of the non-septal wall of the left ventricle, the ventral part of the interventricular septum, part of the infundibulum, the left atrium and part of the right atrium. At its origin it is larger than the right coronary artery. The ventral and dorsal septal arteries have an unusual course lying in the subendocardial tissue of the right ventricle. It is believed that arteries in this position have not been described previously. The great cardiac vein opens directly into the right atrium. A typical coronary sinus is present but formed only from veins draining the dorsal aspect of the heart. It is concluded that the coronary circulation in T. vulpecula closely resembles that of the avian heart and is unlike both the monotreme and placental mammalian patterns.     

The arterial blood supply of the conducting system in normal human hearts

The distributing artery of the conducting system of the heart is occasionally injured in cardiac surgery. The aim of this study was to define the anatomic characteristics of the principal arterial source of the sinu-atrial node and atrioventricular node. Furthermore, the morphology of the tendon of Todaro was clarified. Thirty hearts were studied by gross anatomic methods, and the exact area of the conducting system was supported by histologic observations of four hearts. The sinu-atrial node was supplied by the right coronary artery more frequently (73% of cases) than by the left (3%), and in 23% of cases this node was supplied by both coronary arteries. The atrioventricular node was supplied by the right coronary artery (80% of cases) more than by the left (10%), and in 10% of the cases this node was supplied by both coronary arteries. The atrioventricular bundle branch arose from the right coronary artery in 10% of cases, the left coronary artery in 73%, and both coronary arteries in 17%. Most of the blood to the right bundle (the moderator band) was supplied by the interventricular septal branches of the anterior interventricular branch from the left coronary artery. Finally, all the arteries of the right bundle and left bundle were defined to be derived from left coronary arteries.     

Arterial vascularization of the human moderator band: an analysis of this structure's role as a collateral circulation route

In the human heart, the moderator band, or trabecula septomarginalis, is a muscle column that courses inferiorly from the right portion of the interventricular septum to the base of the anterior papillary muscle of the right ventricle This muscular structure is crossed by one or more arteries, which come from the anterior interventricular artery and perfuses the anterior papillary muscle of the right ventricle. In order to clarify the arterial supply of this muscle column, we studied 28 adult hearts, free of any signs of coronary disorder. The path of the moderator band artery was followed by means of microdissection, and we studied the source, course, and interconnections made with other arteries. We observed that the source of the moderator band artery lies in the first three anterior septal arteries, most often in the second one. In relation to the short axis of the heart, the artery of the moderator band can either follow a horizontal path to the septal papillary muscle of the right ventricle or an oblique route to the moderator band, depending on the position of its source. In all the hearts studied, the moderator band artery made anastomotic connections at the base of the anterior papillary muscle of the right ventricle with various branches of the right coronary artery, which means that it can play a key role in collateral circulation following obstruction of the epicardium coronary arteries.     

Anatomy and vasculature of a minke whale heart

The heart from a 4-m-long minke whale (Balaenoptera acutorostrata) was studied to determine the details of its anatomy and to consider cardiac adaptations to diving. The volume fraction (Vvc) of capillaries in the wall of the left ventricle was determined at different levels from base to apex and at different depths from epi- to endocardium using a light microscopic stereologic technique. Typical of cetaceans, this minke whale heart was distinctly flattened dorsoventrally. A moderator band, characteristic of ungulate hearts, spanned the right ventricle. The right and left atrioventricular valves were tricuspid and bicuspid, respectively. The right coronary artery supplied the dorsal and right lateral myocardium. The left coronary artery supplied the ventral and left lateral myocardium. An anastomosis between the dorsal and ventral interventricular arteries occurred in the dorsal interventricular groove. Stereologically, a decreasing transmural gradient in Vvc was identified between the epicardium and the subepicardium at 15 cm from the apex. Our results, however, did not reveal any significant deviations in the pattern of capillary distribution in the wall of the left ventricle between this baleen whale and terrestrial mammals. Measurements of the heart, great vessels, coronary vasculature, and ventricular walls are also given, and they suggest a physiologic and adaptive right ventricular hypertrophy. Based on these and other observations, we propose that the relatively great thickness of the right ventricle and the distinctive shape of the cetacean heart are adaptations to the hemodynamic changes and collapse of the thorax associated with apneic diving.     

Coronary artery distribution in bonnet monkeys (Macaca radiata)

Full use of nonhuman primates as a model for coronary vascular disease has been hampered by several factors, including the limited availability of detailed coronary anatomic data. This study was undertaken to identify the gross coronary arterial anatomy of the Bonnet monkey (Macaca radiata). The hearts of sixteen adult male Bonnet monkeys were subjected to postmortem coronary angiography and gross morphological examination. The main left coronary artery divided into the left anterior descending coronary artery (LAD) and the left circumflex coronary artery (LCA). The posterior descending coronary artery (PDCA) arose from the LCA in 31% of the cases and from the right coronary artery (RCA) in 56% of the hearts. Hearts from two animals (13%) had paired arteries, arising from the LCA and RCA, located in the posterior interventricular groove. The arterial supply to the sinoatrial node originated from the LCA in 69% of the animals and from the RCA in the remainder. The atrioventricular node was supplied by a branch of the RCA in 69% of the animals and from the LCA in the remainder. The coronary anatomy of the bonnet monkey resembles that of man more closely than does the dog in terms of origin of the PDCA, supply of the sinoatrial and atrioventricular nodes, and perfusion of the interventricular septum. The Bonnet monkey may therefore be a useful model for certain specific pathophysiological studies on the coronary circulation.     

Posterior right diagonal artery

Background: There is general confusion about a branch of the posterior segment of the right coronary artery that has been referred to as 1) the lower trunk of a divided right coronary artery; 2) a posterior reflection of the right marginal artery; 3) the ramus lateralis; and 4) a posterolateral branch or a posterior descending artery. Materials: Three hundred human hearts were studied by direct observation, X-ray films, and corrosion casting. Results: This branch of the right coronary artery arises either after the right marginal artery (in 84% of hearts) or it constitutes the continuation of this artery in the remaining 16%. We named it the posterior right diagonal artery (PRDA). It was found in 14% of 266 hearts of right dominant type. It was present in 39% when the length of the posterior descending artery (PDA) was shorter than half of the length of the posterior interventricular sulcus (PIS) and in 6% when it was longer. When the PRDA originated directly from the RCA, the RMA appeared underdeveloped; the PRDA always occupied the inferior part of the PIS and appears either as continuation of a short PDA or as a replacement for a long PDA from the point where this artery leaves the PIS to enter the posterior wall of the left ventricle. The PDRA when present serves as a bridge between the RCA and the left anterior descending artery. Conclusions: These findings are of practical importance for the correct interpretation of coronary arteriographies and in the field of coronary artery surgery. © 1994 Wiley-Liss, Inc.     

The relationship of myocardial bridges to coronary artery dominance in the adult human heart

Myocardial bridging is recognized as an anatomical variation of the human coronary circulation in which an epicardial artery lies in the myocardium for part of its course. Thus, the vessel is 'bridged' by myocardium. The anterior interventricular branch of the left coronary artery has been reported as the most common site of myocardial bridges but other locations have been reported. The purpose of this study was to provide more definitive information on the vessels with myocardial bridges, the length and depth of the bridged segment, and the relationship between the presence of bridges and coronary dominance. Two hundred formalin-fixed human hearts were examined. Myocardial bridges were found in 69 (34.5%) of the hearts with a total of 81 bridges. One bridge was found in 59 of these hearts and multiple bridges were observed in ten (eight with double bridges and two with triple bridges). Bridges were most often found over the anterior interventricular artery (35 hearts). Bridges were also found over the diagonal branch of the left coronary artery (14), over the left marginal branch (five) and over the inferior interventricular branch of the left coronary artery (six). Bridges were also found over the right coronary artery (15 hearts), over the right marginal branch (four) and over the inferior interventricular branch of the right coronary artery (two). The presence of bridges appeared to be related to coronary dominance, especially in the left coronary circulation. Forty-six (66.6%) of the hearts with bridges were left dominant. Forty-two of these had bridges over the left coronary circulation and four over the right coronary circulation. Seventeen hearts (24.6%) were right dominant. Eleven of these had bridges over the right coronary circulation and six over the left coronary circulation. The remaining six hearts were co-dominant with four having bridges over the left coronary circulation and two over the right coronary circulation. The mean length of the bridges was 31 mm and the mean depth was 12 mm. The possible clinical implications of myocardial bridging may vary from protection against atherosclerosis to systolic vessel compression and resultant myocardial ischaemia.     

Origin and course of the coronary arteries in normal mice and in iv/iv mice

This paper reports on the origin and distribution of the coronary arteries in normal mice and in mice of the iv/iv strain, which show situs inversus and heterotaxia. The coronary arteries were studied by direct observation of the aortic sinuses with the scanning electron microscope, and by examination of vascular corrosion casts. In the normal mouse, the left and right coronaries (LC, RC) arise from the respective Valsalva sinus and course along the ventricular borders to reach the heart apex. Along this course the coronary arteries give off small branches at perpendicular or acute angles to supply the ventricles. The ventricular septum is supplied by the septal artery, which arises as a main branch from the right coronary. Conus arteries arise from the main coronary trunks, from the septal artery and/or directly from the Valsalva sinus. The vascular casts demonstrate the presence of intercoronary anastomoses. The origin of the coronary arteries was found to be abnormal in 84% of the iv/iv mice. These anomalies included double origin, high take-off, slit-like openings and the presence of a single coronary orifice. These anomalies occurred singly or in any combination, and were independent of heart situs. The septal artery originated from RC in most cases of situs solitus but originated predominantly from LC in situs inversus hearts. Except for this anomalous origin no statistical correlation was found between the coronary anomalies and heart situs or a particular mode of heterotaxia. The coronary anomalies observed in the iv/iv mice are similar to those found in human hearts. Most coronary anomalies appear to be due to defective connections between the aortic root and the developing coronaries. iv/iv mice may therefore constitute a good model to study the development of similar anomalies in the human heart.     

Investigation of coronary arteries in the porcupine (Hystrix cristata) by latex injection and angiography

Coronary arteries were investigated in the porcupine by means of angiography performed on each of 5 adult porcupines (3 male, 2 female) which was followed by injection of a colored latex mixture from the aortic arch for the demonstration of these arteries. The results showed that the aorta branched out at the level of the cardiac outlet to form the left and right coronary arteries and right ramus coni arteriosi. Coronary arteries coursed and ramified in the myocardium. The left coronary artery divided to form the paraconal interventricular artery and left circumflex artery when it reached the coronary sulcus. The interventricular septum was vascularized by the septal branch of the paraconal interventricular artery and by the small septal branches. The left and right coronary arteries gave off all the branches reported in the literature for other species. When the ramus coni arteriosi originates from the right coronary artery, it is designated a third coronary artery. In conclusion, it was found that the coronary arteries of the porcupine had an "intramyocardial course" as in other rodents. The coronary supply of the heart represented a "left coronary type" which was similar to those of carnivores and ruminants. The results of this study may contribute to the data in this area of science.     

A Study of Coronary Dominance in the Population of Assam

With the ever increasing load of coronary heart disease, an in-depth study of the coronary arteries has been felt by the medical fraternity. Coronary arteries show wide variations among different populations. These region based variations have not been dealt with enough in the standard books. The knowledge of these variations are of paramount importance when considering various surgical interventions. This study therefore aims to focus on the pattern of coronary dominance in Assam which is ethnically unique from the rest of India. Seventy cadaveric hearts were studied. The population under study included the population of Assam. The coronary arteries were examined by gross dissection and analyzed statistically. The modes of termination of the right coronary artery and the circumflex artery were described with the help of five points: at the right border, between the right border and the crux, at the crux, between the crux and the left border and at the left border. Origin of the posterior interventricular artery was taken as the basis of dominance. Right dominance was found in 70%, left dominance was found in 18.57% while balanced pattern was observed in 11.43% hearts. The results of the study were compared with other authors and variations were noted.     

The anatomy of the coronary sinus and its tributaries

The coronary sinus and its tributaries were studied by anatomical dissection in 37 adult human cadaveric hearts, which had been fixed in formalin solution. An anastomosis of approximately 1.0mm in calibre was observed between the anterior and posterior interventricular veins in 19% of specimens. Myocardial bridges were detected above the anterior interventricular vein or its tributaries in 8% of specimens. The great cardiac vein formed the base of the arteriovenous trigone of Brocq and Mouchet with the bifurcating branches of the left coronary artery in 89% of specimens and formed an angle accompanying these arterial branches in 11%. In the trigone the anterior interventricular and great cardiac veins were superficial to the arteries in 73% of specimens. The left marginal vein was present in 97% of specimens, emptying into the great cardiac vein in 81% of cases and into the coronary sinus in the remaining 19%. The small cardiac vein was present in 54% of specimens. In the coronary sulcus the great cardiac vein was adjacent to the circumflex branch of the left coronary artery in 76% of specimens and to the right coronary artery in 5% in 19% there was no relationship with either artery. The coronary sinus maintained a relationship with the right coronary artery in 46% of specimens and with the left coronary artery in 32% in 22% it had no relationship with these vessels.     

Intersection patterns of human coronary veins and arteries

Intersections between the coronary veins (CV) and arteries (CA) of 103 adult human hearts were mapped on the heart surface. Then the correlations of these intersection patterns to their localization were studied. Eight spots were selected where one of four major CV (anterior cardiac vein, middle cardiac vein, left posterior ventricular vein, and great cardiac vein) intersected with one of CA and their branches (right coronary artery, posterior interventricular branch, left posterior ventricular branch, circumflex branch, diagonal branch, and anterior interventricular branch). The great cardiac vein (GCV) ran beneath the anterior interventricular branch in 56 specimens out of 103, beneath the diagonal branch in 75 specimens out of 103, and beneath the circumflex branch in 36 specimens out of 103, while the other CV mostly ran over CA. The present observations suggest that the CV on the right side may be formed prior to CA, while the CV on the left side may be formed simultaneously with CA.     

The relative anatomy of the coronary arterial and venous systems

An anatomical understanding of human coronary arterial and venous systems is necessary for device development and therapy applications that utilize these vessels. We investigated the unique use of contrast‐CT scans from perfusion‐fixed human hearts for three‐dimensional visualization and analysis of anatomical features of the coronary systems. The coronary arterial and venous systems of eleven perfusion‐fixed human hearts were modeled using contrast‐CT and Mimics software. The coronary arteries that coursed near the major coronary veins, how close coronary arteries were to coronary veins, and the size of adjacent coronary arteries were recorded and analyzed. The majority of coronary veins were within 5 mm of a coronary artery somewhere along its length. Interventricular veins elicited the largest occurrence of overlaps. There was significant variability in the percentage of each vein that coursed within 0.5, 1, 2, and 5 mm of a nearby artery. The left marginal veins and anterior interventricular vein had the largest portion of the vein that coursed near a coronary artery. The right coronary artery most often coursed near the middle cardiac vein. The inferior veins of the left ventricle elicited the most variation in adjacent arteries. The left circumflex artery and/or branches of the circumflex artery coursed near the left marginal vein in all cases where there was an artery near the marginal vein. The wide variation of measurements reinforces the importance of a precise understanding of individualized cardiac anatomy in order to provide the highest quality care to cardiac patients. Clin. Anat. 27:1023–1029, 2014. © 2014 Wiley Periodicals, Inc.     

Terminal branching pattern of the right coronary artery in left-dominant hearts: a cadaveric study

BackgroundLeft coronary dominance has been reported to be associated with increased mortality and severity in case of myocardial ischemia involving left coronary artery. The present cadaveric study was proposed to objectively study and document the termination and branching pattern of the right coronary artery in left-coronary-dominant hearts in relation to the blood supply to the posterior surface of the right ventricle.MethodsSeventy-five cadaveric hearts were studied. The coronary vessels were injected with colored cellulose acetate butyrate and dissected. The coronary dominance was determined. In left-dominant hearts, branches and termination of the right coronary artery were studied.ResultsLeft coronary dominance was found in 13% of the specimens. The number of ventricular branches was found to be present as 0, 1, 2, and 4 in two, four, two, and two of the cases, respectively. The average length of the ventricular branch was 12.7 mm with a range of 5–35 mm. The atrial branch was found in 50% of hearts, varying from 2 to 3 mm in length. In three hearts, the acute marginal artery did not give any posterior ventricular branch, while two, three, and five posterior ventricular branches were seen in four, two, and one heart(s), respectively. The length of the posterior ventricular arteries was between 5 and 15 mm.ConclusionThe RCA is an inconstant and unreliable source of posterior right ventricular perfusion in a significant percentage of population with left-coronary-dominant hearts. This might be the reason for the increased morbidity and mortality seen in the event of left coronary ischemia.     

犬左冠状动脉前室间支心肌桥的形态学特征

目的探讨犬壁冠状动脉和心肌桥的形态学特点,为比较解剖学提供资料。方法取犬心41例,10%甲醛溶液固定,解剖显示冠状动脉及其分支,观测心肌桥及壁冠状动脉的出现率。结果犬冠状动脉心肌桥多出现于前室间支、后室间支和左室前支。心肌桥出现率70.7%,前室间支79.3%,心肌桥厚度为0.56±0.61 mm。前室间支前段内径1.64±0.46 mm,厚度0.18±0.06 mm;壁冠状动脉内径1.35±0.46 mm,厚度0.13±0.04 mm。心肌桥近段距第一对角支距离为19.78±8.20 mm,距前室间支起始部距离为24.49±12.37mm,距右冠起始部距离为24.21±5.80 mm。心肌桥纤维走向与壁冠状动脉夹角为68.94±14.38。结论犬冠状动脉心肌桥出现率及位置与人相似,可作为科研动物模型。     

Narrowed lumen of the right coronary artery in chronic Chagasic patients is associated with ischemic lesions of segmental thinnings of ventricles

Thinning of myocardial segments, mainly at the apex and basal posterior region of left ventricle, are frequent lesions in chronic chagasic cardiopathy (CCC), but still without a well determined etiology. Previously we found severe myocardial microvascular dilatation that could cause ischemia in watershed regions. In this study we analyzed whether narrowness in epicardial coronary arteries in CCC might explain these thinned ventricular lesions. Two groups of dilated hearts with similar weights were compared: eleven hearts from patients with CCC versus four hearts from patients with dilated cardiomyopathy (IDCM). As normal controls we studied three non dilated normal weight hearts. There were no atherosclerotic plaques in the main branches of epicardial coronary arteries and cross-sectional luminal areas of proximal and distal segments were histologically measured. It was found that CCC hearts presented a lower mean luminal area in the right coronary artery (RCA) branch than IDCM, in proximal (4.3 +/- 1.4 vs 6.6 +/- 2.0 mm2; p=0.02) and in distal (1.6 +/- 1.0 vs 3.4 +/- 0.9 mm2; p=0.01) segments, with no statistical differences with normal hearts (2.7 +/- 1.3 and 1.5 +/- 0.3 mm2) in proximal (p=0.2) and distal (p=0.11) sections. In conclusion thinning of ventricular wall in CCC patients seems to be ischemic lesions in the peripheral territory irrigated by the right coronary artery, possibly due to a steal phenomenon by the left coronary, induced by micro vessels dilatation.     

A very rare anatomic variation of the right ventricular branch: right ventricular descending branch from the anterior interventricular branch

The anterior interventricular branch of the left coronary artery has the most constant distribution in the human heart and rarely gives off right ventricular branches. Here we report a case with a right ventricular branch which diverged from the anterior interventricular branch and descended on the anterior right ventricular wall parallel to the anterior interventricular sulcus; we termed it the right ventricular descending branch. This artery gave a collateral artery to the occluded anterior interventricular branch at the apex, and had prevented anterior myocardial infarction. The right ventricular descending branch should be precisely identified in order to perform successful myocardial revascularization procedures such as coronary artery bypass grafting and percutaneous coronary intervention, especially in a patient with anterior interventricular branch occlusion.     

Anatomy of the coronary arteries in fetal pigs: comparison with human anatomy

In this study, 94 fetal pigs were used to comprehensively investigate the origins, number, location, and distribution of the coronary arteries to enrich knowledge on the coronary circulation in fetal pigs, and allow comparison with adult pigs and humans. In fetal pigs, the posterior interventricular sulcus branch always arose from the right coronary artery and the circumflex artery was rarely extended to the posterior interventricular sulcus, while it is variable in humans. In fetal pigs, there was sometimes anastomosis (8.5%) between the left and right conus branches as nutrient arteries of the pulmonary cone. Other branches were not significantly different between fetal pigs and humans, including the acute marginal branch, obtuse marginal branch, and sinoatrial nodal artery. Coronary dominance was also similar. In conclusion, compared with adult pigs, dissection of the coronary arteries in fetal pigs provided a more faithful overview of the porcine coronary circulation. The coronary arteries in fetal pigs were also more suitable for comparison with humans when pigs are used as experimental animals for studying the coronary vessels, which could be an important reference for investigation of clinical treatment of the coronary arteries. In summary, our data provide reliable information about the distribution and ramifications of the coronary arteries, and could be useful for clinicians and surgeons who wish to comprehensively understand coronary anatomy.