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Variations of azygos vein: a cadaveric study with clinical relevance
Ananya Priya1, Shalom Elsy Philip2, Anjali Jain3
1Department of Anatomy, Rajendra Institute of Medical Sciences, Ranchi, India.
Insights
The azygos vein exhibits significant morphological variations in its formation and termination. Understanding these anatomical differences is crucial for preventing thromboembolic events and guiding surgical procedures.
Area of Science:
- Anatomy
- Vascular Biology
- Human Morphology
Background:
- The azygos vein system, including the hemiazygos and accessory hemiazygos veins, displays considerable anatomical variability.
- Variations in the azygos vein can be associated with thromboembolic complications, particularly in younger individuals.
Purpose of the Study:
- To systematically document the morphological and morphometric variations of the azygos vein system.
- To provide detailed anatomical data relevant to clinical practice and surgical interventions.
Main Methods:
- Dissection of the azygos vein from its origin to termination in 30 adult human cadavers.
- Observation and recording of variations in root formation, termination level, and course.
Main Results:
- The azygos vein was formed by a single root in 56.7% of cases.
- Two-rooted formations (lateral and intermediate roots) occurred in 36.7%, and two-rooted formations (lateral and medial roots) in 6.6%.
- Termination at the T4 vertebral level was most common (70%), followed by T3 (20%) and T5 (10%).
Conclusions:
- Significant morphological variations exist in the azygos vein system.
- Awareness of these variations is essential for surgeons performing procedures in the thorax, mediastinum, and retroperitoneum.
- Anatomical knowledge aids in preventing surgical complications and managing vascular pathologies.
Abstract:
The azygos vein can be formed as a single root, two roots, and three roots, namely lateral, intermediate and the medial roots respectively. The hemiazygos vein and the accessory hemiazygos vein are the tributaries of azygos vein rather than its left side equivalents. Its variations, especially in young persons without any relevant risk factors, may result in thromboembolic illness. This study aimed to describe the morphological and morphometric variations of azygos system of veins. The present study was conducted on thirty formalin fixed adult human cadavers by dissecting azygos vein from formation to termination and variations were noted. The azygos vein was formed by a single root in 56.7%, by two roots: the lateral root and intermediate root in 36.7% cases and by the lateral root and medial root in 6.6%. The vertebral level of termination of azygos vein was seen at the level of T4 vertebrae in 70% cases, at the level of T3 vertebrae in 20% of cases and at the level of T5 vertebrae in 10% cases. The course of azygos vein was varying in 13.3%. These morphological variations can be useful while performing mediastinal surgery, mediastinoscopy, surgery of the deformations of the vertebral column, neurovascular surgeries of the retroperitoneal organs, disc herniation and fracture of thoracic vertebrae.
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