Anterior intercostal arteries

Dr Craig Hacking et al.

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 interocostal space, the anterior intercostal artery divides in to paired branches:

  • the larger (main) branch courses laterally in the upper aspect of their respective intercostal space between the internal and innermost intercostal arteries, 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.

Thoracic anatomy
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Article information

rID: 55381
System: Vascular
Section: Anatomy
Synonyms or Alternate Spellings:

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    Figure 1: intercostal space
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