VSD: Diagram of Types of VSD
Anatomic drawing depicting the location of the different types of ventricular septal defects. Subpulmonary defects are caused by deficiency of the conal septum. Membranous defects are located behind the septal leaflet of the tricuspid valve. Atrioventricular (AV) canal type defects are caused by deficiency of the endocardial cushion component of the interventricular septum. Muscular defects can occur in any portion of the muscular septum. The diagram does not depict malalignment defects. Anterior malalignment of the conal septum causes subpulmonary obstruction and is associated with tetralogy of Fallot. Posterior malalignment of the conal septum causes subaortic obstruction and can be associated with coarctation or interrupted aortic arch.