Vascular supply and venous drainage of the chest wall

the intercostal space receives its blood supply from anterior & posterior intercostal arteries.
the anterior intercostal arteries are branches of internal thoracic artery & its terminal branch musculophrenic artery.
lowest 2-spaces has no anterior intercostal supply.
The posterior intercostal arteries are much longer & the first 2-3 arises from superior intercostal branch of costocervical trunk which itself is a branch of 2nd part of subclavian artery.
The lower 9 are the branches of thoracic aorta.
The anterior intercostal veins drain in to the internal thoracic vein & posterior intercostal veins in to azygous & hemiazygous system.