Angelini A, Ho S Y, Anderson R H, Davies M J, Becker A E
Department of Paediatric Cardiac Morphology, Cardiothoracic Institute, London.
Br Heart J. 1988 Jun;59(6):712-6. doi: 10.1136/hrt.59.6.712.
The mitral annulus is the point at which the atrial and ventricular walls meet the base of the mitral valve cusps. The suggestion that a variant of this arrangement termed "disjunction" was associated with prolapse of the leaflets prompted examination of the mitral atrioventricular junctions in seven normal hearts and six with prolapse owing to floppy mitral valves. A complete cord-like ring of connective tissue that encircled the atrioventricular junction and into which the three components were inserted at the same point was found in only one heart. The remaining hearts all showed a mixture of segments in which either the three components were inserted into a cord or simply met. Disjunction, defined as a separation of the atrial wall-mitral valve junction from the other component, the left ventricular wall, can occur both with and without a cord-like annulus. There was no significant difference in the number of segments around the left atrioventricular junction which showed disjunction in hearts with normal or prolapsing leaflets. The feature termed disjunction is an anatomical variation of the normal morphological characteristics of the left atrioventricular junction.
二尖瓣环是心房壁和心室壁与二尖瓣瓣叶基部相接之处。有一种被称为“分离”的这种结构变体与瓣叶脱垂相关的说法，促使人们对7颗正常心脏以及6颗因二尖瓣黏液样变性而出现脱垂的心脏的二尖瓣房室连接部进行了检查。仅在1颗心脏中发现了一个完整的结缔组织索状环，它环绕着房室连接部，且三个组成部分在同一点插入其中。其余的心脏均显示出不同节段的混合情况，其中要么三个组成部分插入一条索状物中，要么只是相接。分离被定义为心房壁 - 二尖瓣连接部与另一组成部分即左心室壁的分离，它在有或没有索状瓣环的情况下均可发生。在瓣叶正常或脱垂的心脏中，左房室连接部周围显示分离的节段数量没有显著差异。被称为分离的这一特征是左房室连接部正常形态特征的一种解剖变异。
