Abstract: Objectives: This study was designed for Sound understanding of the pathological anatomy of artioventricular septal defects (AVSD), emphysizing its surgical importance, connecting it to the surgical techniques have developed for proper surgical repair. Methods: In a systematic review of the literatures had described the surgical anatomy, techniques of the surgical repair, early or late postoperative complications, and long term outcomes of AVC surgeries, there are 110 8articles published in the time period between 1960 and 2013 directly discussing these varieties. The total of 10 separated important structural differences between AVC anatomy and normal hearts were reported and demonstrated their direct or indirect effects on the surgical techniques and outcomes. Results: Along with variations in the degrees of incomplete development of the three basic elements characterizing AVSD, there are other seven important anomalies involving the level of the attachments of the AV valves to the crest of the inter-ventricular septum, abnormal dimension of the inlet and outlet septum to ventricular apex, different contribution of attachments of valve leaflets to common A-V valve annular circumference, variable position of the common A-V valve in relation to the plane of the ventricular septum, different position and pathway of the conductive tissue, and unwedged position of the aortic valve away from AV valves with absent or hypoplastic aortomitral Curtin. Conclusion: Pathological anatomy of AVSDs are not only the septal and AV valve malformations to be considered during surgery, they include other many associated structural anomalies that affect the techniques and results of surgical repair.