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BACKGROUND: The azygos vein (AV) plays a crucial role in the mediastinal region, exhibiting considerable variability in its anatomy and relationship with surrounding structures. This study aims to assess the morphometry and anatomy of the AV through a comprehensive meta-analysis of studies reporting extractable data on this vessel. MATERIALS AND METHODS: Major online medical databases such as PubMed, Scopus, ScienceDirect, Web of Science, SciELO, BIOSIS, Current Content Connect, Korean Journal Database and Wiley online library were searched to gather all relevant studies regarding the anatomical characteristics of the AV. RESULTS: The results of the present meta-analysis comprised 40 studies, categorized into eight groups for data analysis. The mean AV diameter at its origin was set at 3.86 mm (SE = 0.84). The most prevalent was type IIB, with a prevalence of 40.23% (95% CI: 29.06-51.92%). The pooled prevalence of the right subcostal and right ascending lumbar veins forming the AV was 73.82% (95% CI: 55.77-88.67%). CONCLUSIONS: The AV exhibits a high degree of variability regarding its origin, trajectory, and connections with the hemiazygos system. The most prevalent type of AV, according to the Anson and McVay classification, was Type II (transitional type). Moreover, the vein was found to be formed by the right subcostal and the right ascending lumbar veins in the majority of the cases. This is the most comprehensive and current assessment of AV morphometry and anatomy to date. The findings are a valuable resource for physicians, especially surgeons performing various procedures in the mediastinum.
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BACKGROUND: To conduct a morphological and morphometric analysis of the sacral hiatus (SH) using lumbosacral spine CT scans and to evaluate its clinical relevance in caudal epidural analgesia (CEA). MATERIALS AND METHODS: This retrospective study analyzed 77 lumbosacral spine CT scans from a diverse patient population. The shape of the SH was classified into common types: inverted U, inverted V, irregular, and bilobed. Morphometric measurements included the length, width, and depth at the apex of the SH. The apex level of the SH was also determined in relation to the sacral vertebrae, and statistical analysis was performed to identify any correlation between the apex level and the morphometric dimensions. RESULTS: The most frequent SH shape was inverted U (68.83%), followed by inverted V (20.77%), irregular (9%), and a single instance of a bilobed shape (1.29%). The apex of the SH was most commonly located at the level of the S4 vertebra (75.32%), followed by the S3 vertebra (20.77%), S5 in two (2.59) and S2 in one (1.29%). No significant correlation was found between the level of the apex and the length, width, or depth of the SH. These findings indicate a high degree of anatomical variability in the SH, independent of the apex level. CONCLUSIONS: The anatomical variability of the SH, as observed in this study, underscores the need for individualized assessment during CEA. The lack of correlation between the apex level and the morphometric dimensions of the SH highlights the importance of imaging modalities such as ultrasound or fluoroscopy to ensure precise localization and effective analgesia administration. These insights can improve clinical outcomes by enhancing the accuracy and safety of caudal epidural procedures.
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Anatomical nomenclature commonly does not follow changes in the clinical language and demands. Therefore we tried to explain the pelvic relationships based on the changes that occur in the pelvis as well as to compare different nomenclatural strategies used in every day language. Courses of fasciae in the male and female pelvis are also considered.