Anatomical variants of the azygos system: azygos system variants

Introduction: the conformation of the azygos venous system is variable, it is formed by the azygos vein, the hemiazygos and the accessory hemiazygos. Arranged in parallel with respect to the vena cava, it is important as an alternative route for the venous return to the heart. Materials and method:...

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Autores principales: Cabrera Frola, Juan A., Berke, Andrés, Ignatov, María, Armand Ugón, Gustavo
Formato: Artículo revista
Lenguaje:Español
Publicado: Asociación Argentina de Anatomía Clínica (Argentine Association of Clinical Anatomy) 2020
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Acceso en línea:https://revistas.unc.edu.ar/index.php/anatclinar/article/view/28137
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Sumario:Introduction: the conformation of the azygos venous system is variable, it is formed by the azygos vein, the hemiazygos and the accessory hemiazygos. Arranged in parallel with respect to the vena cava, it is important as an alternative route for the venous return to the heart. Materials and method: 12 adult cadavers and 12 computed tomography scans of adult patients of both sexes. It was registered: type of azygos system (according to Anson classification), caliber at origin and termination of azygos and hemiazygos veins, vertebral level of completion of each one. Results: 14 (58%) female cases, 10 (42%) male cases. Type II was found in 14 (58%) cases, distributed in 9 (38%) cases of subtype 2A, 3 (12%) cases of subtype 2B, 1 (4%) case of subtype 2D, 1 (4%) case of subtype 2C. Type III was found in 9 (38%) cases. 1 (4%) type I case was found. The average caliber of the azygos vein origin was 4.2mm (2mm-7.7mm), and the hemiazygos vein was 3mm (2mm-6.9mm), The termination caliber of the azygos vein was 8.3mm (4.2mm-10.3mm), for the hemiazygos vein it was 4.9mm (3.3mm-7.2mm). The mean vertebral level of the azygos vein was T4 with 14 (58%) cases and the hemiazygos vein T8 with 8 (28.5%) cases. Conclusion: the type of azygos system is variable, and does not correlate with that described by classical authors, but with contemporary authors. There is a great correlation with different authors on the vertebral levels of termination of azygos, hemiazygos and accessory hemiazygos.