Anterior intercostal arteries

Last revised by Yoshi Yu on 27 Mar 2023

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 intercostal artery, accompanying vein and nerve courses in the layer between the internal and innermost intercostal muscles. The anterior intercostal artery divides into paired branches within each intercostal space:

  • the larger (main) branch courses laterally in the upper aspect of their respective intercostal space, 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. 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.


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.


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.

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Cases and figures

  • Figure 1: intercostal space
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