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.     

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.     

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.     

Observation of root variations in human coronary arteries

In dissection courses conducted from 1999 through to 2003, five specimens were found to have coronary arteries with variant roots and branches, as follows: in specimens 1-4, roots of the right coronary artery (RCA) and right conus branch arose independently from the right aortic sinus (RAS); in specimen 5, the RCA and left coronary artery (LCA) originated from the RAS. The LCA pierced the upper part of the muscular interventricular septum and appeared on the surface, then dividing into the anterior interventricular and the circumflex branches. In the present study, we considered that the right conus arteries in specimens 1-4 were the remnant blood capillaries around the aorta towards the RAS in the embryonic stage. In specimen 5, the vessel near the left aortic sinus was poorly developed as a small thin artery. Instead, the LCA was developed from the anterior and posterior interventricular septal branches.     

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.     

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.     

Anomalous first septal perforator artery: Anatomic-clinical correlates

The interventricular septum is considered the most densely vascularized portion of the heart, containing important elements of the cardiac conduction system and providing mechanical support for both right and left ventricular function. Anatomically, this structure is perfused by the relatively small caliber anterior and posterior septal perforator branches arising from two large epicardial coronary vessels, the anterior interventricular (descending) branch of the left coronary artery and the posterior interventricular (descending) branch of the right coronary artery, respectively. In cases of significant atherosclerotic disease depriving flow in the major coronary vessels and their septal branches, an anomalous septal perforator artery can take over the task of supporting the function of the interventricular septum by supplementing essential collateral flow. © 1996 Wiley-Liss, Inc.     

动脉圆锥的动脉解剖学观察

目的 动脉圆锥的动脉解剖学观察。方法 在50例经动脉灌注红色乳胶的成年国人尸体上及在5例冠状动脉塑型标本上解剖观察心脏动脉圆锥的动脉供应。结果 动脉圆锥的动脉大都来源于右冠状动脉的圆锥支和左冠状动脉前室间支的动脉圆锥支,它们大都在动脉圆锥部吻合。结论 本文研究了动脉圆锥部的动脉供应及其吻合,为临床应用提供了形态学依据。     

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.     

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.     

A case of anomalous bronchial artery ramified from coronary artery

There have been no anatomical reports on the origin of the bronchial artery derived from the coronary artery. In a 2006 cadaveric dissection course, an anomalous bronchial artery that reached the middle lobe of the right lung from the left coronary artery was observed in an 88-year-old Japanese man. In this specimen, the circumflex branch of the left coronary artery passed under the left auricle in the coronary sulcus and bifurcated to three branches (left marginal branch, posterior left ventricular branch, atrial branch), which were 3.2–3.4 mm in diameter. The atrial branch intersected on the surface of the great cardiac vein, ran along the oblique vein of the left atrium, and reached the atrial side of the transverse pericardial sinus, and then divided into two branches. One of them led to the right atrium. The other branch passed between two right superior pulmonary veins, which derived from superior and middle lobes of the right lung, respectively, through the hilum of the lung along the right superior pulmonary vein derived from the middle lobe, and finally became the bronchial artery in the middle lobe of the right lung. In the middle lobe, the bronchial artery divided into a thin branch along the pulmonary vein for the lateral segment, ran along the surface of the right middle bronchus, and then reached the medial segment, being wedged between the segmental bronchus and vein.     

Origin of anterior descending coronary artery from right aortic sinus. Intramyocardial tunneling to left side of heart

We report a rare case of a coronary anomaly. All of the coronary arteries originated from a single ostium located in the right coronary cusp. The single coronary artery had a main branch corresponding to the usually dominant right coronary artery. The left anterior descending coronary artery arose from the right coronary artery and coursed intramyocardially within the right ventricular outflow tract to the anterior interventricular sulcus. The absence of evidence of myocardial ischemia in our patient, both clinically and at autopsy, and in three cases reported previously, suggests that the condition reported here was an unlikely cause of myocardial ischemia.     

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.     

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.     

Myocardial bridges over coronary arteries in Cercopithecus.

The presence of myocardial bridges over the coronary arteries has been studied in 29 monkey (Cercopithecus aethiops) hearts. The great resemblance between the Cercopithecus subepicardial arterial net with the corresponding one in humans has been revealed. There is a high incidence (83%) of myocardial bridges only over the ventricular branches of both coronary arteries. Myocardial bridges are usually (90%) located over the left coronary artery branches, and the left anterior interventricular branch is the most frequently (69%) overbridged vessel. The bridges are always single over the vessel examined and their length varies from 0.5 mm to 31.6 mm. No statistically significant sexual difference in myocardial bridges distribution is reported.     

Functional dominance of the right coronary artery: Incidence in the human heart

After injection of radiopaque medium, 200 human hearts were studied by direct observation and x-ray analysis. The right coronary artery (RC) was dominant in 178 of these hearts as characterized by giving off the typical posterior interventricular artery (PIV), the posterior descending artery. Within this group, 19 specimens had right coronary arteries that gave off both a large posterior interventricular artery (LPIV) and a branch that continued beyond the crux termed a large extension of the right coronary (LERC). The subgroup of hearts supplied thusly was termed real right dominant (RRD). The RC in these hearts supplied the right ventricle and almost half of the left ventricle. These findings explain why proximal lesions of the RC in RRD hearts can be associated with extensive posterolateral ischemia and mitral dysfunction and should be of practical importance when considering angioplasty or by-pass surgery. The diameters and lengths of the arteries of the RC in RRD hearts were measured and compared with the same parameters in typical right dominant hearts. © 1996 Wiley-Liss, Inc.     

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.     

Dual anterior interventricular artery type IV: a rare anatomical variation

Type IV dual anterior interventricular artery (AIVA) is a rare variant that involves bilateral connection of this vessel to the left main coronary artery and right coronary artery or right aortic sinus. We present a case of such a variant where the ectopic branch traveled an intraseptal course, i.e., through the superior aspect of the crista supraventricularis in a subendocardial position and then intramyocardially inside the upper interventricular septum to reach the anterior interventricular sulcus and descend toward the apex. In a left anterior oblique view, this course lacked the typical caudal anterior loop but it was recognized by virtue of emergence of a septal branch as the first branch of the ectopic AIVA. Recognition of this variant and differentiation among the possible courses of the ectopic branch is important for patient management.