posterior collateral intercostal artery (anatomy)

Last reviewed 01/2018

Each posterior intercostal artery divides at the level of the angle of the superior rib within each interspace to give:

• a main branch which continues laterally within the subcostal groove of the superior rib
• a collateral intercostal branch which passes inferiorly to the superior margin of the inferior rib within each interspace

Alike the main branch, each collateral intercostal artery:

• runs in the plane between internal oblique and the innermost intercostals
• anastomoses with an anterior artery from either the internal thoracic or musculophrenic arteries