Multiple variations in the azygos venous system: a preaortic interazygos vein and the absence of hemiazygos vein

Özdemir, Bülent; Aldur, M. Mustafa; Çelik, H. Hamdi

doi:10.1007/s00276-002-0008-7

Cited by 12 publications

(11 citation statements)

References 4 publications

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“…Embryologically, this variation can be explained by nonregression of the terminal parts of the posterior cardinal veins. Similar variation was reported by Srinivasa Rao Y et al (7) The role of left superior intercostal vein in serving as the terminal conduit for the upper left posterior thorax has also been emphasised in yet another report presented by Özdemir et al (8) Similarly persistence of cranial segment of posterior cardinal vein was also reported by Mahato et al (9) Variation 3: In the third type of variation noted, there were numerous retroaortic transverse anastomoses between the azygos system and the hemiazygos venous system; this is classified as transition type anomaly or type II anomaly. (10) Embryologically, it can be explained by persistence of the venous channels between the azygos lines on the two sides.…”

Section: Accessory Hemiazygos Vein Is Absentsupporting

confidence: 72%

The Azygos Venous System and Its Anatomical Variations

Rao¹,

Banerjee²

2016

jebmh

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AIMS AND OBJECTIVES Azygos veins are important cavocaval and portacaval junctions, which form a collateral circulation in caval vein occlusion and in portal hypertension, cirrhosis of liver. The unpaired azygos venous system consists of azygos vein, hemiazygos vein and accessory azygos vein. This system of veins, along with its mediastinal, bronchial and oesophageal tributaries drains most of the body wall of trunk, namely posterior abdominal and thoracic wall. Anatomical variations of this unpaired azygos venous system are clinically important. AIMS To study and report the occurrence of anatomical variations of the unpaired azygos venous system in the region of East Godavari District, Andhra Pradesh (India). METHODS The present study was carried out in the Department of Anatomy, KIMS & RF, Amalapuram and G.S.L. Medical College, Rajahmundry over a period of 2 years. The present study was conducted on 60 cadavers (irrespective of age and sex). The entire course of the azygos venous system in these 60 cadavers was carefully observed and documented. RESULTS Anatomical variations were present in 16.66% of cases, out of which three distinct types were identified. 6.6% exhibited two separate azygos venous systems with no communications, 5% with communication between the left brachiocephalic vein and the azygos vein and 5% presence of post-aortic venous channels. CONCLUSION Variations of azygos venous system may be wrongly dubbed as aneurysm, lymphadenopathy or other abnormalities while reporting a CT scan of mediastinum. Venous anomalies are also detected only during surgery. The most troublesome intraoperative hazard is haemorrhage, which is mainly of venous origin. To avoid such situations is to have an awareness and knowledge of the expected venous anomalies.

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Section: Accessory Hemiazygos Vein Is Absentsupporting

confidence: 72%

The Azygos Venous System and Its Anatomical Variations

Rao¹,

Banerjee²

2016

jebmh

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“…[8] The absence of hemiazygos vein and presence of preaortic interazygos vein has also been reported. [9] Our literature survey also revealed a case where the hemiazygos vein was absent with the presence of right and left azygos veins. [10] Another very rare variation associated with the azygos system of veins is opening of all pulmonary veins into the azygos vein.…”

Section: Discussionmentioning

confidence: 90%

A unique variation of azygos system of veins

Badagabettu

Shetty

D’Souza

2016

J Cardiovasc Echography

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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.

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“…The interazygos veins can be formed by independent left posterior intercostal veins uniting to form a common trunk, the hemiazygos, accessory hemiazygos veins or the commonly found hemiazygos -accessory hemiazygos anastomosis (Celik et al, 1996;Gilkeson et al, 1997;Ozbek et al, 1999;Ozdemir et al, 2002). Preaortic interazygos veins can be joined by other posterior intercostal veins as in the reports by Das & Paul (2004) and Pyrzowski et al, or accompanied by additional retroaortic anastomoses as in the report by Ozdemir et al In our reports however, the interazygos vein in both cases was not accompanied by any pre or retroaortic vessels.…”

Section: Discussionmentioning

confidence: 99%