Vascular supply and venous drainage of the chest wall
The intercostal spaces receive their arterial supply from the anterior and posterior intercostal arteries.
• The anterior intercostal arteries are branches of the internal thoracic artery and its terminal branch the musculophrenic artery. The lowest two spaces have no anterior intercostal supply .
• The first 2–3 posterior intercostal arteries arise from the superior intercostal branch of the costocervical trunk, a branch of the 2nd part of the subclavian artery . The lower nine posterior intercostal arteries are branches of the thoracic aorta. The posterior intercostal arteries are much longer than the anterior intercostal arteries.
The anterior intercostal veins drain anteriorly into the internal thoracicand musculophrenic veins. The posterior intercostal veins draininto the azygos and hemiazygos systems .