Arterial vascularization of the human moderator band: An analysis of this structure's role as a collateral circulation route

In the human heart, the moderator band, or trabecula septomarginalis, is a muscle column that courses inferiorly from the right portion of the interve ntricular septum to the base of the anterior papillary muscle of the right ventricle This muscular structure is crossed by one or more arteries, which come from the anterior interventricular artery and perfuses the anterior p apillary muscle of the right ventricle. In order to clarify the arterial su pply of this muscle column, we studied 28 adult hearts, free of any signs o f coronary disorder. The path of the moderator band artery was followed by means of microdissection, and we studied the source, course, and interconne ctions made with other arteries. We observed that the source of the moderator band artery lies in the first three anterior septal arteries, most often in the second one. In relation t o the short axis of the heart, the artery of the moderator band can either follow a horizontal path to the septal papillary muscle of the right ventri cle or an oblique route to the moderator band, depending on the position of its source. In all the hearts studied, the moderator band artery made anas tomotic connections at the base of the anterior papillary muscle of the rig ht ventricle with various branches of the right coronary artery, which mean s that it can play a key role in collateral circulation following obstructi on of the epicardium coronary arteries. (C) 2000 Wiley-Liss, Inc.