Abnormal right ventricle morphology Anomalous muscle bundle of the right ventricle 2016-03-13T10:09:33Z UMLS:C4280792 Right ventricular anomalous muscle bundle An accessory (not normally present) muscle bundle in the right ventricle which obstructs the right ventricular outflow tract. The anomalous muscle bundle is triangular in shape, with its apex attached to the anterior aspect of the ventricular septum immediately above and in front of the ventricular septal defect. It crosses the right ventricular chamber to insert at the apical portion of the anterior wall of the right ventricle (PMID:708529).