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Systemic Veins of the Thorax.
Published in Fred W Wright, Radiology of the Chest and Related Conditions, 2022
In about 1% of people the azygos lobe is a normal variant (Illus. AZ LOBE+VN). Sometimes the hemiazygos vein is predominant with a large left sided intercostal vein arch and a very small azygos arch.
Anatomy of veins and lymphatics
Published in Ken Myers, Paul Hannah, Marcus Cremonese, Lourens Bester, Phil Bekhor, Attilio Cavezzi, Marianne de Maeseneer, Greg Goodman, David Jenkins, Herman Lee, Adrian Lim, David Mitchell, Nick Morrison, Andrew Nicolaides, Hugo Partsch, Tony Penington, Neil Piller, Stefania Roberts, Greg Seeley, Paul Thibault, Steve Yelland, Manual of Venous and Lymphatic Diseases, 2017
Ken Myers, Paul Hannah, Marcus Cremonese, Lourens Bester, Phil Bekhor, Attilio Cavezzi, Marianne de Maeseneer, Greg Goodman, David Jenkins, Herman Lee, Adrian Lim, David Mitchell, Nick Morrison, Andrew Nicolaides, Hugo Partsch, Tony Penington, Neil Piller, Stefania Roberts, Greg Seeley, Paul Thibault, Steve Yelland
The hemiazygos vein usually continues from the left ascending lumbar vein, and passes up through the left crus of the diaphragm to ascend on the left side of the vertebral column. It passes to the right across the vertebral column behind the aorta, oesophagus and thoracic duct at about the level of the ninth thoracic vertebra, to end in the azygos vein. The hemiazygos vein may be connected above to the accessory hemiazygos vein, the two of them being a mirror of the azygos vein on the right side.
Development and anatomy of the venous system
Published in Peter Gloviczki, Michael C. Dalsing, Bo Eklöf, Fedor Lurie, Thomas W. Wakefield, Monika L. Gloviczki, Handbook of Venous and Lymphatic Disorders, 2017
The origin of the azygos vein is not constant. It may arise from the back of the inferior vena cava at the level of the renal veins or it may be the continuation of the right ascending lumbar vein (Figure 2.11). The azygos vein ascends on the right side of the body until the fourth thoracic vertebra and then passes anteriorly to join the superior vena cava. Major tributaries of the azygos vein are the right superior intercostal, the hemiazygos, and the accessory hemiazygos veins. The hemiazygos vein courses on the left side of the vertebral column and its origin is similar to that of the azygos vein. At the level of the eighth thoracic vertebra, it crosses the column and joins the azygos vein. Often, the left renal vein communicates with the hemiazygos vein. The accessory hemiazygos vein descends left to the vertebral column and parallel with the azygos vein. Proximally, it anastomoses with the left brachiocephalic vein and ends distally when it joins to the azygos or the hemiazygos veins at the level of the seventh thoracic vertebra. The azygos veins drain the intercostal veins on both sides, receive several visceral tributaries, and freely anastomose with the vertebral venous plexuses. The azygos veins and their tributaries provide important collateral circulation in the face of superior or inferior vena cava obstruction.
Insertion of a totally implantable venous access port in a patient with persistent left superior vena cava (PLSVC)
Published in Acta Chirurgica Belgica, 2018
Julie Van Walleghem, Sofie Depuydt, Stijn Schepers
Failure of this embryological evolution gives rise to a ‘persistent’ left-hand sided superior vena cava with multiple possible anatomical configurations. Most of the PLSVC patients (up to 90%) present with a bilateral superior vena cava. Sixty-five percent of these ‘double’ superior vena cava patients have no bridging innominate vein and the right superior vena cava usually is somewhat smaller. The arrangement of azygos and hemiazygos veins as well as the cardiac drainage of the PLSVC can be variable. In approximately 90% of patients, the PLSVC drains into the right atrium through the coronary sinus, resulting in no hemodynamic consequences. Nevertheless a remaining 10% drain into the left atrium, causing a right-to-left cardiac shunting and an accompanying risk of paradoxical emboli [1].
An expert spotlight on inferior vena cava filters
Published in Expert Review of Hematology, 2021
Anil Pillai, Manoj Kathuria, Maria del Pilar Bayona Molano, Patrick Sutphin, Sanjeeva P Kalva
The IVC is a single right-sided retroperitoneal vessel, in approximately 97% of patients. It is formed at the confluence of the common iliac veins and drains into the right atrium with major draining veins including the hepatic and renal veins. Embryologically, the intrahepatic IVC develops from the vitelline veins and infra- and suprarenal segments from the right supracardinal and subcardinal veins respectively. The left supracardinal vein involutes and constitutes hemiazygos veins [56,57]. Variations in typical anatomy of the IVC require different approaches to planning placement of an IVC filter.