A Case Series Cadaveric Study on Acquired and Congenital Azygos Venous System Variations

The azygos venous system holds essential clinical relevance as it can provide collateral circulation in cases where the superior and inferior vena cava become obstructed. Additionally, it is important in imaging and mediastinal procedures because variations in this system may be confused with pathology. In this study, the azygos system of 31 embalmed anatomy donors was dissected, analyzed, and classified according to the Anson McVay system and Dahran and Saomes subclassification. Out of 31 donors, one (3.22%) donor was classified as Type I, 27 (87.09%) were Type II, two (6.45%) were Type III, and one (3.22%) was unobservable. These values closely replicated values previously reported in literature; however, four subjects exhibited variations that are rare or not previously reported in literature. In this paper, we describe those rare cases and consider their development and clinical relevance