Anterior intercostal arteries
The intercostal spaces are supplied by pairs of posterior and anterior intercostal arteries.
Gross Anatomy
The 1st to 6th anterior intercostal arteries arise directly from the lateral aspect of the internal thoracic artery. The 7th to 9th arise from the musculophrenic artery, a branch of the internal thoracic artery.
In each intercostal space, the anterior intercostal artery divides into paired branches:
- the larger (main) branch courses laterally in the upper aspect of their respective intercostal space between the internal and innermost intercostal muscles, below the intercostal vein and above the intercostal nerve (mnemonic "VAN"), protected by the costal groove of the rib above.
- the smaller (collateral) branch descends into the lower aspect of their respective intercostal space and courses laterally between the internal and innermost intercostal arteries. Here they are not offered protection by the rib above.
In the 2 most inferior intercostal spaces (10th and 11th spaces), the anterior intercostal artery is absent, with the posterior intercostal artery supplying each space solely.
Branches
As these arteries course laterally within the intercostal spaces, they give off a variable number of small perforating cutaneous branches. In the lateral aspect of the thoracic wall, the artery anastomoses with branches of the posterior intercostal artery.
Supply
Along with the posterior intercostal arteries, the anterior intercostal arteries supply the muscles and skin within the intercostal spaces as well as the parietal pleura.
Related Radiopaedia articles
Anatomy: Thoracic
- thoracic skeleton
- thoracic cage
- thoracic spine
- articulations
- muscles of the thorax
- diaphragm
- intercostal space
- intercostal muscles
- variant anatomy
- spaces of the thorax
- thoracic viscera
- tracheobronchial tree
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lungs
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bronchopulmonary segmental anatomy (Boyden Classification) (mnemonic)
- left lung
- right lung
- variant anatomy
- lung parenchyma
- hilum
- pleura
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bronchopulmonary segmental anatomy (Boyden Classification) (mnemonic)
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heart
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coronary arteries
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left main coronary artery (LMCA)
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circumflex artery (LCx)
- obtuse marginal branches (OM1, OM2, etc))
- Kugel's artery
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left anterior descending artery (LAD)
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right coronary artery (RCA)
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pericardium
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- vein of Marshall (oblique vein of the left atrium)
- anterior cardiac veins
- venae cordis minimae (smallest cardiac veins or thebesian veins)
- cardiac veins which drain into the coronary sinus
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- thoracoepigastric vein
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