Azygos vein - wikipedia Azygos vein Azygos vein Superior vena cava, inferior vena cava, azygos vein and their tributaries. ( Vena azygos labeled at center. ) POSTERIOR VIEW : The position and relation of the esophagus in the cervical region and in the posterior mediastinum. Seen from behind. ( Azygos vein labeled at bottom left. ) Details Precursor Right supracardinal vein Source superior intercostal vein Drains to superior vena cava Identifiers Latin vena azygos MeSH A07. 231.908. 106 Dorlands / Elsevier v_05 / 12849551 TA A12. 3.07. 001 FMA 4838 Anatomical terminology ( edit on Wikidata ) The azygos vein is a vein running up the side of the thoracic vertebral column draining itself towards the superior vena cava. It connects the systems of superior vena cava and inferior vena cava and can provide an alternative path for blood to the right atrium when either of the venae cavae is blocked. Contents 1 Structure 2 Function 3 Clinical significance 4 History 5 Additional images 6 See also 7 References 8 External links Structure The azygos vein transports deoxygenated blood from the posterior walls of the thorax and abdomen into the superior vena cava vein. The anatomy of this blood vessel can be quite variable. In some rare variations for example, it also drains thoracic veins, bronchial veins and even gonadal veins. The vein is so named because it has no symmetrically equivalent vein on the left side of the body. It is formed by the union of the ascending lumbar veins with the right subcostal veins at the level of the 12th thoracic vertebra, ascending in the posterior mediastinum, and arching over the right main bronchus posteriorly at the root of the right lung to join the superior vena cava. This `` arch of the azygos vein '' ( arcus venae azygos ) is an important anatomic landmark. As an anatomical variation in 1 - 2 % of the population, the arch can be displaced laterally, thereby creating a pleural septum separating an azygos lobe from the upper lobe of the right lung. A major tributary is the hemiazygos vein, a similar structure on the opposite side of the vertebral column. Other tributaries include the bronchial veins, pericardial veins, and posterior right intercostal veins. It communicates with the vertebrael venous plexuses. Function The azygos system of veins is considered to be the azygos vein, along with its left - sided counterparts, the hemiazygos vein and the accessory hemiazygos vein. Clinical significance Azygos vein abnormalities can be inferenced on chest radiograph by enlargement of the azygos vein shadow greater than 1 cm. False positives can occur in heart failure causing increased pressures on the right side of the heart, or adjacent lymphadenopathy. History The Greek root zyg refers to a pair. ' A - ' means not. Thus, azygos means unpaired. The azygos vein is unpaired in that there is only one in the body, mostly on the right side. While there is the hemiazygos vein and its accessory on the left side of the body, they are considered tributaries of the azygos vein rather than its left - side equivalent. This terminology is only accurate in some species, such as the human, dog and cat. Ruminants ( such as sheep and cows ) have paired azygos veins. Additional images Diagram showing completion of development of the parietal veins. The venæ cavæ and azygos veins, with their tributaries. Mediastinal surface of right lung. Azygos vein Azygos vein See also Hemiazygos vein Posterior intercostal veins Superior vena cava Chronic cerebrospinal venous insufficiency References Jump up ^ Edward Lamperti ; Michael Schuenke ; Erik Schulte ; Udo Schumacher ; Ross, Lawrence J. ( 2006 ). General Anatomy and Musculoskeletal System ( Thieme Atlas of Anatomy ). Thieme Publishing Group. p. 13. ISBN 3 - 13 - 142081 - 2. Jump up ^ http://www.clinicalimaging.org/article/S0899-7071%2899%2900141-2/abstract Jump up ^ http://library.prognosisapp.com/case/Emergency/Superior-Vena-Cava-Syndrome Jump up ^ Berman, Gerald de Lacey, Simon Morley, Laurence ( 2008 ). The chest X-ray : a survival guide. Philadelphia, PA : Saunders / Elsevier. ISBN 978 - 0702030468. External links Anatomy figure : 19 : 03 - 03 at Human Anatomy Online, SUNY Downstate Medical Center - `` Right side of the mediastinum. '' Dissection at lumc.edu Radiology at umich.edu Function at Knowyourbody.net Veins of the thorax and vertebral column Thorax Coronary Coronary sinus Great cardiac ( Left marginal ) Posterior of the left ventricle Oblique of the left atrium ( Ligament of the left vena cava ) Middle cardiac Small cardiac vein Anterior cardiac ( Right marginal ) Smallest cardiac veins Right atrial veins Right ventricular veins Pulmonary right inferior pulmonary vein right superior pulmonary vein left inferior pulmonary vein left superior pulmonary vein superior vena cava Brachiocephalic internal thoracic anterior intercostal superior epigastric left superior intercostal supreme vertebral subclavian axillary : lateral thoracic thoracoepigastric dorsal scapular external jugular pericardiacophrenic internal jugular Azygos right superior intercostal bronchial intercostal / posterior intercostal 5 - 11 accessory hemiazygos / hemiazygos superior phrenic Vertebral column vertebral venous plexuses external internal spinal posterior anterior basivertebral intervertebral Retrieved from `` https://en.wikipedia.org/w/index.php?title=Azygos_vein&oldid=793145330 '' Categories : Veins of the torso Hidden categories : All articles with dead external links Articles with dead external links from October 2016 Articles with permanently dead external links Medicine infobox template using GraySubject or GrayPage Medicine infobox template using Dorlands parameter Talk Contents About Wikipedia Azərbaycanca Čeština Deutsch Español فارسی Français Hrvatski Italiano Latina Nederlands 日本 語 Polski Português Edit links This page was last edited on 30 July 2017, at 22 : 58. 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Question: the azygos vein drains what part of the body
Answer: thorax