Accessory hemiazygos vein at a glance
- What it is
- The accessory hemiazygos vein is a thoracic vein on the left side of the vertebral column that drains the upper left posterior intercostal spaces.
- Location
- It begins from the left posterior intercostal veins of roughly the fourth to eighth spaces, descends along the left side of the vertebral bodies and crosses behind the thoracic aorta, usually at the T7-T8 level, to join the azygos vein. It may also communicate with the hemiazygos vein.
- Function
- It carries blood from the upper left posterior thoracic wall to the azygos system, which empties into the superior vena cava.
- Body system
- Cardiovascular · single, midline structure
- FMA ID
- FMA5011 (Foundational Model of Anatomy)
Key facts
- It is part of the azygos system, a collateral route between the superior and inferior venae cavae.
- It also receives the left bronchial veins and sometimes the mid-oesophageal veins.
Structures next to the accessory hemiazygos vein
The nearest named structures in the 3D model, measured from the centre of each part:
- Esophagus · digestive
- Main bronchus proper · respiratory
- Cavity of atrium · cardiovascular
- Main bronchus · respiratory
- Ascending aorta · cardiovascular
- Posterior cusp of aortic valve · cardiovascular
- Arch of aorta · cardiovascular
- Wall of atrium · cardiovascular
- Bronchial artery · cardiovascular
- Intervertebral disk of fifth thoracic vertebra · skeletal
References
- Foundational Model of Anatomy: Accessory hemiazygos vein (FMA5011). EMBL-EBI Ontology Lookup Service.
- OpenStax. Anatomy and Physiology 2e, §20.1 Structure and Function of Blood Vessels. Rice University, 2022.
- Mitsuhashi N. et al. (2009). BodyParts3D: 3D structure database for anatomical concepts. Nucleic Acids Research 37, D782–D785. Data © The Database Center for Life Science, CC BY 4.0.
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