Aim: To study and analyze the common as well as rare anatomical variations of the azygos venous system along with their embryological aspect available in the literature. Background: The azygos system of veins comprises azygos, hemiazygos, and accessory hemiazygos veins that act as a connecting channel between the inferior vena cava and superior vena cava. Results: The review of research studies of the azygos venous system in the literature and in the cadaveric studies demonstrated a wide range of variations in the origin, course, number of tributaries, and termination. The results may contribute to the anatomical knowledge and training of students as well as clinicians in addition to supporting future research. Conclusion: Anatomical variations of the azygos venous system can affect patient outcomes indirectly. Therefore, anatomical knowledge of all possible variations of the azygos venous system should be clearly understood. Clinical significance: Each anomaly of the azygos venous system along with its embryology and clinical significance is of utmost importance for radiologists, surgeons, and clinicians in their respective fields.
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