人心房室结和房室束的光镜观察

HISTOLOGICAL EXAMINATION OF THE A-V NODE AND A-V BUNDLE IN HUMAN HEARTS

本文对13例人心标本房室结和房室束的形态及位置,作了连续切片观察。1.房室结为一扁长形结构,其横切面呈右侧微凸的三角形,有时切面呈梭形或半卵圆形。成人房室结大小为3.5×3.3×1.1 mm^(3)。有5例房室结表面的右心房心内膜隆起。2.房室结位于二尖瓣与三尖瓣附着缘之间的房室隔内,成人房室结距冠状窦口1.8~5.8 mm,距右心房心内膜0.3~0.7 mm,距三尖瓣隔侧瓣上缘3.3~7.5 mm。结左侧紧贴中心纤维体。3.房室结可分为浅、深两部,浅部纤维纵行止于结的下端。1例深部又分为上、下两部。在结表面右心房心内膜隆起的标本上,结右侧的心房肌覆盖层止于心内膜。结的上缘、右侧面及后缘与房肌相连。4.成人房室束长5.7~7.9 mm,直径1.1~1.5 mm。房室束前部有7例在肌性室间隔顶部;3例在肌性室间隔左侧;2例在肌性室间隔肌肉内部。1例经行特殊,由肌性室间隔顶部至其左侧,最后至肌性室间隔内部偏右侧而终止。

The morphology and position of the AV node and AV bundle were observed in 13 human hearts with serial sections.1.the AV node is a long sagittal flatt ened structure,its transverse section is triangular in shape with a right convex surface,sometimes the cross section is fusiform or half oval in shape.Its size is 3.5x3.3x1.1 mm in adult.In 5 cases the endocardium lying on the right surface of the AV node is elevated.2.The AV node is situated in the upper border of the atrioventricular septum(between the levels of the attachment lines of the mitral and tricuspid valves).The adult AV node is 1.8-5.8 mm anterior to the coronary sinus orifice,0.3-0.7 mm from the endocardium of the right atrium,3.3-7.5 mm above the upper border of the septal leaflet of the tricuspid valve.The left surface of the AV node contacts with the central fibrous body.3.The AV node can be divided in 2 parts:superficial and deep,the fibers of the super ficial part are longitudinal in sections and end in the lower border of the AV node.In one case,the deep part is subdivided in an upper part and a lower part.In the specimens in which the right atrial endocardium lying on the right surface of the AV node is elevated,the overlaying fibers end in the endocardium.At the upper border,right surface,and posterior margin of the AV node,there are atrial fibers ending to the AV node.4.The adult AV bundle is 5.7-7.9 mm long,1.1-1.5 mm in diameter.Its anterior part is on top of the muscular interventricular septum in 7 specimens,on its left surface in 3 specimens,and in the substance of the muscular interventricular septum in 2 specimens.In one case its course is very special,at first on the top of muscular interventricular septum,then at its left surface,finally in the substance of the right part of the muscular interventricular septum.