Doménech-Mateu J M, Arnó-Palau A, Martínez-Pozo A
Faculty of Medicine, Department of Anatomy, Autonomous University of Barcelona, Bellaterra, Spain.
Anat Rec. 1991 May;230(1):73-85. doi: 10.1002/ar.1092300108.
We have observed an extra atrioventricular node in the normal heart of a human fetus. It is located in the septal wall of the right atrium, subendocardially, and just where Todaro's tendon leaves this wall to go toward the inferior vena cava valve. In its trajectory, this tendon gives way to a remarkable prominence in the cavity of the right atrium: the sinus band. In order to explain the embryogenesis of this extra atrioventricular node, we have studied the normal development of the atrioventricular specific system and have concluded that the atrioventricular node is formed from a growth and displacement toward the atrium of the primitive atrioventricular specific material, which originates from the myocardium of the posterior wall of the atrioventricular canal. Likewise, during its development, the atrioventricular node keeps in close proximity with the Todaro's tendon. In our view, this accounts for the embryogenesis of the extra atrioventricular node, since a fragment of the atrioventricular node can remain cranial to Todaro's tendon and be displaced by it in a craniodorsal direction. This fragment would then lead to the formation of an extra atrioventricular node like the one present in the heart of the fetus we have examined.
我们在一名人类胎儿的正常心脏中观察到一个额外的房室结。它位于右心房的间隔壁内，心内膜下，恰好在托达罗肌腱离开该壁朝向腔静脉瓣的位置。在其走行过程中，这条肌腱在右心房腔内形成一个显著的隆起：窦带。为了解释这个额外房室结的胚胎发生，我们研究了房室特异性系统的正常发育，并得出结论，房室结是由原始房室特异性物质向心房生长和移位形成的，该物质起源于房室管后壁的心肌。同样，在其发育过程中，房室结与托达罗肌腱保持紧密相邻。我们认为，这就解释了额外房室结的胚胎发生，因为房室结的一个片段可以留在托达罗肌腱的头侧，并被其向颅背方向移位。然后这个片段会导致形成一个像我们检查的胎儿心脏中存在的那样的额外房室结。
