Abstract:

Objective To investigate the morphology and correlation of the atrioventricular node and atrioventricular ring by macro-micro-anatomy of human heart. Methods In 12 hearts, the structural relation between the atrioventricular node, retroaortic node and atrioventricular ring was dissected and mapped under a stereomicroscope and they were further examined using histological methods. Results Nearby the mitral ring and tricuspid ring, the left atrioventricular ring ［diameter=(0.69±0.12) mm］, and right atrioventricular ring ［diameter=(0.78±0.13) mm］ at the frontal region of the coronary sinus ostium were exposed through the stereomicroscope (12/12 hearts). These atrioventricular rings extended to the atrioventricular node through the gap between the atrial and the ventricular myocardium in the atrioventricular septum. The retroaortic node was explored in the atrial septum that was located in the back of aortic root (7/9 hearts). Its posterosuperior part was connected with a bundle of myocardium in the gap between the left and the right atrial myocardium. The left and right atrioventricular rings branched off from the anterior inferior part of retroaortic node. The left ring was thicker than right ring. The retroaortic node was connected directly with the atrioventricular node by the subendocardial myocardium in the back of the central fibrous body. The above connection was different from the left and right atrioventricular rings. Conclusion The retroaortic node and atrioventricular ring can be exposed partly by the stereomicroscope and there are 3 pathways between the retroaortic node and the atrioventricular node.

Key words: Cardiac conduction system, Atrioventricular node, Atrioventricular ring, Atrioventricular bundle, Stereomicrography, Anatomy, Human