part of part of has part has part characteristic of inheres in has modifier Ventricular septal aneurysm Membranous ventricular septal aneurysm 2017-03-17T20:04:30Z The pars membranacea is the last portion of the septum formed in the fetus, is lo-cated between the left and right ventricles in front of the tricuspid valve, and between the left ventricle and the right atrium, behind the tricuspid valve. It lies in close proximity to the aortic and atrioventricular valves and is considered to be the weakest part of the ventricular septum. The aneurysms of the membranous portion usually measure 1 to 2 cm in all diameters and their walls are composed of fibrous tissue forming thick trabeculae when seen from the left ventricle. They can project into different portions of the right ventricle or right atrium. Interventricular septum membranous part aneurysm Bowing (bulging out) of the membranous part of the interventricular septum of more than 10-15 mm into the cavity of an adjacent ventricle (usually into the right ventricle). Fyler:2346 Aneurysm of the membranous ventricular septum aneurysm abnormal increased amount interventricular septum membranous part