[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Chest](https://durgical.com/en/anatomy/region/chest/) › Intercostal veins [Cardiovascular system](https://durgical.com/en/anatomy/system/cardiovascular-system/) · [Chest](https://durgical.com/en/anatomy/region/chest/) # Intercostal veins The intercostal veins run in the groove under each rib and drain the [chest](https://durgical.com/en/anatomy/region/chest/) wall, mostly into the [azygos veins](https://durgical.com/en/anatomy/azygos-vein/) at the back of the chest. Official name: Right posterior intercostal veins [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=thorax&select=intercostal_veins&side=r) Opens in the Durgical app, no sign-up needed. ## What it is Veins running with the intercostal arteries under each rib. ## What it does Drain the chest wall into the azygos system. ## Key points - 1st space: a supreme intercostal vein to the brachiocephalic or [vertebral vein](https://durgical.com/en/anatomy/vertebral-vein/); 2nd–3rd (often 4th): the superior intercostal vein, to the azygos on the right - The left superior intercostal vein crosses the left side of the [aortic arch](https://durgical.com/en/anatomy/aortic-arch/), between the left phrenic and vagus nerves, to end in the left [brachiocephalic vein](https://durgical.com/en/anatomy/brachiocephalic-vein/) - They connect with the valveless vertebral venous plexus, a route by which tumour and infection reach the spine ## Key facts **Drains** Intercostal spaces, chest wall, back muscles and vertebral venous plexus; run highest in neurovascular bundle (VAN) **Into** Posterior: azygos (right), hemiazygos and accessory hemiazygos (left); upper spaces via superior intercostal veins; anterior: internal thoracic ## Relations **Course** From the front of the space, where it connects with the anterior intercostal veins, each runs back in the costal groove between the internal and [innermost intercostal muscles](https://durgical.com/en/anatomy/innermost-intercostal-muscles/), then turns medially over the rib neck to the azygos system **Above** Costal groove of the rib above **Below** The posterior intercostal artery, then the intercostal nerve, lowest and least protected by the groove **Superficial** Internal and [external intercostal muscles](https://durgical.com/en/anatomy/external-intercostal-muscles/) **Deep** Innermost intercostal muscle, endothoracic fascia and parietal [pleura](https://durgical.com/en/anatomy/pleura/); near the [spine](https://durgical.com/en/anatomy/region/spine/) the vein lies almost directly on the pleura ## How to find it At thoracoscopy they show through the parietal pleura in the costal groove on the lower edge of each rib, highest of the three structures in the bundle. Toward the spine the posterior veins converge on the azygos vein on the right and on the hemiazygos veins on the left, along the sides of the vertebral bodies. ## On imaging On a frontal chest X-ray the left superior intercostal vein may show as a small bump on the aortic knob (the aortic [nipple](https://durgical.com/en/anatomy/nipple/)). On contrast CT, dilated intercostal veins point to obstruction of a central vein. ## Clinical notes - Chest drains and pleural needles are passed just above the upper border of the rib below, away from the vein, artery and nerve sheltered in the groove of the rib above - In superior or [inferior vena cava](https://durgical.com/en/anatomy/inferior-vena-cava/) obstruction they become collateral channels through the azygos system - Spread of cancer (for example breast or [prostate](https://durgical.com/en/anatomy/prostate/)) and of infection to the vertebrae through their links with the vertebral venous plexus ## Anatomical variants - Azygos continuation of the inferior vena cava: the azygos system, fed by the intercostal veins, carries blood from the lower body to the [superior vena cava](https://durgical.com/en/anatomy/superior-vena-cava/) - Azygos lobe: a laterally placed azygos arch drags a fold of pleura into the [right upper lobe](https://durgical.com/en/anatomy/superior-lobe-of-right-lung/), seen on X-ray as a curved line ## Development The azygos and hemiazygos system that collects them comes from paired embryonic veins of the back wall; the right side becomes dominant, and the left superior intercostal vein is a remnant of the left-sided system, which is why it still crosses the arch to the left brachiocephalic vein. ## Related conditions - [Haemothorax](https://durgical.com/en/conditions/haemothorax/) ## Test yourself Think of the answer, then tap the question to see it. ## In what order do the vein, artery and nerve lie in the costal groove? Vein highest, then the posterior intercostal artery, then the intercostal nerve lowest and least protected by the groove (VAN). ## Why are chest drains and pleural needles passed just above the upper border of the rib below? To avoid the intercostal vein, artery and nerve sheltered in the costal groove of the rib above. ## Where does the left superior intercostal vein run and end? Across the left side of the aortic arch, between the left phrenic and vagus nerves, to end in the left brachiocephalic vein. ## Why can cancer and infection spread to the vertebrae through the intercostal veins? The intercostal veins connect with the valveless vertebral venous plexus. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/right-posterior-intercostal-veins/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** venae intercostales posteriores dextrae TA2 4750 **Official Spanish (DeCS)** Venas intercostales **English (TA2)** Right posterior intercostal veins Sources: Terminologia Anatomica (TA2); [Anatomy, Thoracotomy and the Collateral Intercostal Neurovascular Bundle](https://www.ncbi.nlm.nih.gov/books/NBK544368/); [Anatomy, Thorax, Azygos Veins](https://www.ncbi.nlm.nih.gov/books/NBK554430/); Anatomy of the Human Body (20th ed.): Development of the Vascular System (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain. ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/right-posterior-intercostal-veins/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/right-posterior-intercostal-veins/