[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/) › Internal thoracic artery [Cardiovascular system](https://durgical.com/en/anatomy/system/cardiovascular-system/) · [Chest](https://durgical.com/en/anatomy/region/chest/) # Internal thoracic artery The internal thoracic artery runs down inside the front [chest](https://durgical.com/en/anatomy/region/chest/) wall beside the breastbone; it supplies the chest wall and breast and is used in bypass surgery. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=thorax&select=internal_thoracic_artery&side=r) Opens in the Durgical app, no sign-up needed. ## What it is An artery running down the inside of the front chest wall, about 1-2 cm beside the [sternum](https://durgical.com/en/anatomy/sternum/) (also called the internal mammary artery). ## What it does Supplies the chest wall and breast. It rarely gets clogged, which makes it the best bypass graft. ## Key points - The left internal thoracic artery grafted to the left anterior descending artery is the conduit of choice in coronary bypass, with excellent long-term patency - Runs about a finger-breadth from the sternal edge, behind the costal cartilages and in front of the pleura and, lower down, the transversus thoracis - Its superior epigastric branch enters the [rectus sheath](https://durgical.com/en/anatomy/rectus-sheath/) through the sternocostal triangle (Larrey cleft) and joins the [inferior epigastric artery](https://durgical.com/en/anatomy/inferior-epigastric-artery/): a collateral route around an aortic coarctation ## Key facts **Origin** First part of subclavian artery; descends about 1 cm lateral to sternum behind costal cartilages **Branches** Pericardiacophrenic (with the phrenic nerve); mediastinal and thymic; anterior intercostals (two per space, spaces 1–6); perforating (2nd–4th enlarged to the breast); ends in 6th space as musculophrenic (spaces 7–9) and superior epigastric **Supplies** Anterior chest wall, breast, [pericardium](https://durgical.com/en/anatomy/pericardium/), [diaphragm](https://durgical.com/en/anatomy/diaphragm/), upper anterior abdominal wall; common coronary bypass graft ## Relations **Course** From the first part of the [subclavian artery](https://durgical.com/en/anatomy/right-subclavian-artery/) it descends behind the medial end of the [clavicle](https://durgical.com/en/anatomy/clavicle/) and the 1st [costal cartilage](https://durgical.com/en/anatomy/costal-cartilage/), is crossed by the [phrenic nerve](https://durgical.com/en/anatomy/phrenic-nerve/), then runs straight down behind the upper six costal cartilages and divides in the 6th intercostal space **In front** Costal cartilages and the front ends of the [internal intercostal muscles](https://durgical.com/en/anatomy/internal-intercostal-muscles/); [pectoralis major](https://durgical.com/en/anatomy/pectoralis-major-muscle/) further out **Behind** Endothoracic fascia and parietal [pleura](https://durgical.com/en/anatomy/pleura/) above; the [transversus thoracis muscle](https://durgical.com/en/anatomy/transversus-thoracis-muscle/) below the 3rd costal cartilage **Medial** Sternal edge; the [internal thoracic veins](https://durgical.com/en/anatomy/internal-thoracic-veins/), which merge into a single vein on its medial side higher up, and the [parasternal lymph nodes](https://durgical.com/en/anatomy/parasternal-nodes/) ## How to find it Not palpable. Its line is projected about a finger-breadth (1–2 cm) lateral to the sternal edge from the 1st to the 6th costal cartilage; parasternal punctures are planned away from this line, and ultrasound shows it as a pulsating vessel deep to the cartilages. ## On imaging On contrast CT it is a small vessel a finger-breadth from the sternal edge, behind the costal cartilages, between its veins. Before bypass, CT or angiography checks it and the subclavian for narrowing; afterwards, CT angiography shows if the graft is open. In coarctation it is enlarged on CT, and rib notching from the intercostal collaterals may show on radiographs. ## Common problems - Rarely diseased. ## Treatment - In bypass surgery the left internal mammary artery is freed and joined to the LAD; it often stays open for decades. ## Clinical notes - Harvested through a median sternotomy as a pedicle with its veins and fat, or skeletonized; taking both arteries reduces sternal blood supply and raises wound risk, especially in diabetes - A narrowing of the subclavian artery before its origin can steal flow from a coronary graft (coronary-subclavian steal), with angina on arm effort - Parasternal stab wounds can cut it and cause a large haemothorax - Used as the recipient artery in free-flap breast reconstruction ## Anatomical variants - Origin and branching vary: usually from the first part of the subclavian artery, occasionally from the thyrocervical trunk or a shared trunk - A lateral costal branch running down the inner chest wall behind the [ribs](https://durgical.com/en/anatomy/ribs/) is present in some people ## Related conditions - [Coarctation of the aorta](https://durgical.com/en/conditions/coarctation-of-the-aorta/) - [Haemothorax](https://durgical.com/en/conditions/haemothorax/) ## Test yourself Think of the answer, then tap the question to see it. ## From which artery does the internal thoracic artery arise, and where does it run in the chest? From the first part of the subclavian artery; it descends about a finger-breadth (1–2 cm) lateral to the sternal edge, behind the upper six costal cartilages. ## What are the two terminal branches of the internal thoracic artery, and where does it divide? The musculophrenic and superior epigastric arteries, in the 6th intercostal space. ## Why is the left internal thoracic artery the conduit of choice in coronary bypass surgery? Grafted to the left anterior descending artery, it rarely clogs and has excellent long-term patency, often staying open for decades. ## What is coronary-subclavian steal? A narrowing of the subclavian artery before the origin of an internal thoracic artery graft steals flow from the coronary graft, causing angina on arm effort. ## How does the internal thoracic artery provide a collateral route around an aortic coarctation? Its superior epigastric branch joins the inferior epigastric artery in the rectus sheath. [Add to my cards (5)](https://durgical.app/estudiar/?add=/en/anatomy/internal-thoracic-artery/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** arteria thoracica interna; rami intercostales anteriores arteriae thoracicae internae TA2 4576 **Official Spanish (DeCS)** Arterias mamarias DeCS D008323 **English (TA2)** Internal thoracic artery **Also called** internal mammary artery · mammary arteries · LIMA · arteria mammaria interna ## Related - [Sternum](https://durgical.com/en/anatomy/sternum/) - [Pectoralis major](https://durgical.com/en/anatomy/pectoralis-major-muscle/) - [External intercostals](https://durgical.com/en/anatomy/external-intercostal-muscles/) - [Thymus](https://durgical.com/en/anatomy/thymus/) - [Pericardium](https://durgical.com/en/anatomy/pericardium/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=8496&filter=ths_termall&q=Arterias%20Mamarias); [Anatomy, Thorax, Internal Mammary (Internal Thoracic) Arteries](https://www.ncbi.nlm.nih.gov/books/NBK537337/); Tratado de anatomía humana (9.ª ed.), tomo II, Libro IV Angiología, arterias subclavia, axilar, humeral, radial y cubital, arcos palmares y vías anastomóticas del miembro superior. ## **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/internal-thoracic-artery/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/internal-thoracic-artery/