Watch this animated slide view to learn about the steps involved in the septation of truncus arteriosus and an overview of formation of interventricular septum. Timeline: 0:00 - Introduction 0:16 - Muscular ventricular septum formation 1:54 - Formation of conotruncal ridges and aorticopulmonary septum 2:37 - Formation of membranous ventricular septum 3:27 - Spiral movement of aorticopulmonary septum 3:36 - Final pulmonary trunk and aorta