Anderson R H, Zuberbuhler J R, Penkoske P A, Neches W H
J Thorac Cardiovasc Surg. 1985 Oct;90(4):605-10.
A full understanding of the morphology of atrioventricular septal defects ("endocardial cushion defects," "atrioventricular canal malformations") demands knowledge of the exact nature of three specific breaches in the skirt of valve leaflet tissue guarding the atrioventricular junction. One of these is the space between the left ventricular components of the two leaflets that are enclosed in both the right and left ventricles (the bridging leaflets). Traditionally described as a cleft, it has been suggested more recently that this gap functions as a commissure. The second space is that which is found anteriorly and superiorly in the so-called Rastelli type A malformation. This is also called a cleft in a common anterior leaflet, but it has been suggested that it too is a commissure. The final breach is that produced by the surgeon when he divides the free-floating superior bridging leaflet if repairing the so-called Rastelli type C malformation with a one-patch technique. It is generally agreed that this breach be considered a division. To adjudicate the nature of the other breaches, it is necessary to compare them with commissures in atrioventricular and arterial valves and with the isolated cleft that exists in the aortic leaflet of a normal mitral valve. These considerations show that the gap between the left ventricular components of the bridging leaflets functions as a commissure even though it is not supported by a papillary muscle. This would not be expected, since the commissural attachments of the leaflets are in the left and right ventricle, respectively. The gap seen anteriorly in the Rastelli type A malformation is also a commissure, being supported in typical fashion by the medial papillary muscle of the right ventricle.
要全面了解房室间隔缺损（“心内膜垫缺损”、“房室管畸形”）的形态，需要知晓在守护房室交界处的瓣膜小叶组织裙边中三个特定缺口的确切性质。其中之一是在左右心室均有包绕的两个小叶的左心室部分之间的间隙（桥接小叶）。传统上称为裂隙，最近有人提出这个间隙起到连合的作用。第二个间隙是在所谓的Rastelli A型畸形中在前上方发现的间隙。这在共同的前叶中也称为裂隙，但也有人提出它也是一个连合。最后一个缺口是外科医生在使用单片技术修复所谓的Rastelli C型畸形时，将游离的上方桥接小叶分开时产生的。人们普遍认为这个缺口应被视为一种分离。为了判定其他缺口的性质，有必要将它们与房室瓣和动脉瓣中的连合以及正常二尖瓣主动脉瓣叶中存在的孤立裂隙进行比较。这些考量表明，桥接小叶的左心室部分之间的间隙起到连合的作用，尽管它没有乳头肌的支撑。这是出乎意料的，因为小叶的连合附着分别位于左心室和右心室。在Rastelli A型畸形中在前侧看到的间隙也是一个连合，由右心室的内侧乳头肌以典型方式支撑。
