THE ATRIAL ARTERY IN CHINESE I. THE BRANCHING, CALIBER AND DISTRIBUTION OF THE ATRIAL ARTERY / 解剖学报

ABSTRACT

1. 50 heart specimens (30 ABS cast and 20 dissected specimens) were used to study the origin, course and diameter of the branches of the atrial artery. And some measurements were made. 2. Most of the S-A node artery are the first or second anterior atrial branch. In 26 cases (52%), it arises from the right coronary artery, with a diameter of 1.2～ 2.2mm; and in 24 cases (48%)from the left coronary artery, with a diameter of 1.1～ 2.0mm. Their courses are closely related with the anterior interatrial sulcus and the interatrial muscular bundle. Most of the right and left S-A node arteries take a counter-clockwise course and end at the orifice of the superior vena cava. During their course around the orifice of the superior vena cava, a descending loop is present in the posterior interatrial sulcus, only in two cases which is different from McAlpine's observation. Only in 6 cases the origin of the S-A node artery is at the other site, i. e. 4 from left circumflex atrial artery, and 2 from the extension of the terminal branch of the right coronary artery. 3. Kugel's artery usually arises from these branches of the promixal part of the right or left coronary artery, i. e. from the left or right S-A node artery, or from the left or right anterior atrial artery. It usually penetrates into the septum at the anterior interatrial sulcus, with a diameter of 0.1～1.2mm, during penetration. In the septum it has a constant course around the inferior border of the fossa ovalis and may be anastomosed with the branches of the right and left coronary artery at the posterior wall of the atrium. This is an important collteral circulation of the coronary artery. 4. A-V node artery usually arises from the right coronary artery, 94%; and only a small portion, 6%, from the left coronary artery. Its diameter is around 0.4～1.9 mm. Usually only one A-V node artery is present. Double A-V node artery is observedonly in 2 cases both of them are arising from the right coronary artery. In 2 cases, A-V node artery arises from the posterior ventricular branches, penetrates into the posterior wall of the left ventricule, runs between the right and left atrioventricular foramin and reaches the A-V node. In 44.23% of the 50 specimens, A-V node artery take its origin from the top of the "U" turn of the coronary artery at the crux. In 36.5% of the specimen the artery originates from the plain straight type of coronary artery; in the other 19.24% though the "U-turn" is present, but the artery does not originate from the top of the turn. The course of the artery is generally along the midline between the right and left atrio-ventricular foramina, and rarely along the borders of the left or right afrioventricular foramina. 5. The clinical importances of the topographical characteristics are discussed.