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Updated: Oct 27, 2026
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Published on: April 18, 2013
Anatomical presentation of the azygos venous system in a South African population: a donor body study
Vivian B Mathole1, Abduljalil A Adebesin2
1Department of Anatomy and Histology, Sefako Makgatho Health Sciences University, Pretoria, South Africa. matholevivian@gmail.com.
Background:
Variations in the azygos venous system (AVS) are not uncommon and underscore the need for proper classification and awareness to ensure accurate radiological interpretation and increased caution during surgical procedures. This study evaluated anatomical variations in the AVS in a South African donor population using the modified Anson and McVay classification.
Materials And Methods:
This descriptive study included 60 adult South African donor bodies of both sexes. Fine anatomical dissections were performed to expose the AVS along with adjacent vertebrae. Photographic documentation and schematic illustrations were created to record observations. The AVS was classified into Types 1, 2, or 3 based on the number and anatomical relationship of retroaortic communications between the azygos and hemiazygos systems, following the classification described by Anson and McVay. The vertebral levels of these communications were also documented.
Results:
Of the 60 donor bodies examined, Type 2 was the most frequently observed pattern, accounting for 90% (n = 54). Within this group, Group B was identified in 37.0% of cases (n = 20), while Group E was observed in 11.1% of cases (n = 6). Types 1 and 3 were each identified in 5% (n = 3) cases. In 60% of cases (36 out of 60), the left-to-right crossings of the azygos system occurred at the T7 and T8 thoracic vertebral levels.
Conclusions:
This study demonstrates notable anatomical variations in the AVS. Awareness of these variations is essential during mediastinal imaging to avoid misinterpretation as pathological conditions such as tumors, lymphadenopathy, or aneurysms.
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