Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Case Reports
. 2016 Apr-Jun;26(2):61-64.
doi: 10.4103/2211-4122.183761.

A Unique Variation of Azygos System of Veins

Satheesha Nayak Badagabettu  1 , Prakashchandra Shetty  1 , Melanie Rose D'Souza  1
Affiliations
Case Reports

A Unique Variation of Azygos System of Veins

Satheesha Nayak Badagabettu et al. J Cardiovasc Echogr. 2016 Apr-Jun.

Abstract

Knowledge of variations of azygos and hemiazygos veins is of importance to cardiothoracic surgeons and radiologists during various surgical, radiological, and echography techniques. We report some unique variations of azygos system of veins observed during dissection classes for undergraduate medical students. The azygos vein was formed as usual by the union of right subcostal and ascending lumbar veins. The vein ascended upward and to the left to reach the midline at the level of the 9th thoracic vertebra. After ascending till 5th thoracic vertebra, it gradually inclined to the right of midline and terminated by opening into the superior vena cava at the level of the 3rd thoracic vertebra. There was no major variation in the tributaries of the azygos vein on the right side, except that the right superior intercostal vein crossed behind the azygos vein from right to left and opened into the left side of the azygos vein. Further, two anastomotic veins connected the 10th, 11th and 12th posterior intercostal veins with each other to form two anastomotic circles on the right side of 10th to 12th thoracic vertebrae. The hemiazygos vein bifurcated on the left side of the 10th thoracic vertebra and the two ends opened into the azygos vein at the level of 9th and 10th thoracic vertebrae forming a venous circle in front of the 10th thoracic vertebra. The course of accessory hemiazygos vein was noteworthy. Instead of its classic descending course, the vein ascended upward from the left side of the 8th thoracic vertebra till the 6th thoracic vertebra before opening into the azygos vein.

Keywords: Accessory hemiazygos vein; azygos vein; hemiazygos vein; intercostal vein; posterior mediastinum.

PubMed Disclaimer

Conflict of interest statement

There are no conflicts of interest.

Figures

Figure 1
Figure 1
Photograph of dissection of posterior thoracic wall showing the azygos system of veins. AV = Azygos vein, TD = Thoracic duct, SICV = Left superior intercostal vein, HAV = Hemiazygos vein, S = Superior, I = Inferior, L = Left, R = Right
Figure 2
Figure 2
Photograph of dissection of lower part of the posterior thoracic wall as viewed from the right side. AV = Azygos vein, TD = Thoracic duct, T11 = Eleventh thoracic vertebra, AC = Anastomotic venous circle, 10 = Right tenth posterior intercostal vein, 11 = Right eleventh posterior intercostal vein, 12 = Right subcostal vein, S = Superior, I = Inferior, L = Left, R = Right
Figure 3
Figure 3
Photograph of dissection of the posterior thoracic wall as viewed from the left side. AV = Azygos vein, T11 = Eleventh thoracic vertebra, T10 = Tenth thoracic vertebra, T6 = Sixth thoracic vertebra, HAV = Hemiazygos vein, AHAV = Accessory hemiazygos vein, S = Superior, I = Inferior, L = Left, R = Right
Figure 4
Figure 4
A schematic drawing of the azygos vein variation. AV = Azygos vein, HAV = Hemiazygos vein, AHAV = Accessory hemiazygos vein, SICV = Superior intercostal vein, LA = Ascending lumbar vein, AC = Anastomotic venous circle, 1-11 = Posterior intercostal veins, 12 = Subcostal veins
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Alves EC, Porciúncula Junior RW, Monte Bispo RF, de Sousa-Rodrigues CF, da Rocha AC. Formation of the azygos vein. Int J Morphol. 2011;29:140–3.
    1. Arslan G, Cubuk M, Ozkaynak C, Sindel T, Lüleci E. Absence of the azygos vein. Clin Imaging. 2000;24:157–8. - PubMed
    1. Kullnig P, Melzer G, Hausegger K, Einspieler R. Computed tomographic diagnosis of left superior vena cava and absence of the azygos vein: Case report. Cardiovasc Intervent Radiol. 1990;13:47–9. - PubMed
    1. Quraishi MB, Mufti O, Wase A. Absent left and right superior vena cava and azygos continuation of inferior vena cava: A rare anomaly of systemic venous return. J Invasive Cardiol. 2010;22:E159–61. - PubMed
    1. Sieunarine K, May J, White GH, Harris JP. Anomalous azygos vein: A potential danger during endoscopic thoracic sympathectomy. Aust N Z J Surg. 1997;67:578–9. - PubMed

Publication types

LinkOut - more resources