<prompt> The membranous pa of the atrioventricular pa of interventricular septum is betweenRA LVLA RVRA RVLA LV  <response>: Inderbir Singh;s Human embryology; Tenth edition; Pg 244The membranous pa of the interventricular septum is divisible into an anterior pa which separates the right and left ventricle and a posterior pa which separates the left ventricle from the right atrium also called interventricular septum. 