Azygos lobe in a South African cadaveric population

Knowledge of the prevalence, morphology, and location of the azygos lobe is essential for diagnostic and surgical procedures of the lungs related to mediastinal pathologies, especially to minimize intraoperative vascular injuries, shock, possible thoracotomy, and even the possibility of pulmonary torsion. Reports on the prevalence of the azygos lobe vary between 0.11% and 1.06%. The aim of this study was to record the prevalence and morphological description of the azygos lobe in the South African cadaveric population. A total of 704 adult cadavers dissected over a 10-year period by students in the Department of Human Anatomy at the Medunsa Campus, University of Limpopo, were studied. The prevalence and dimensions of the azygos lobe were determined with a 95% confidence interval (CI). Results indicate that an azygos lobe was present in the right lung in only four cases (prevalence 0.57%, 95% CI: 0.2%-1.6%). The mean height and width were 6.7 cm (95% CI: 4.4-9.2) and 4.5 cm (95% CI: 3.7-5.2), respectively. Observations on the morphology of the azygos lobe showed that it was rectangular (n = 3) and triangular (n = 1) in shape with smooth margins. In conclusion, the azygos lobe is a rare anomaly in the South African cadaveric population. The present results are comparable with those reported in the literature for other populations. Future radiological studies on the azygos lobe on living subjects in South Africa will be useful for further understanding of this rare but significant anomaly.