Internal thoracic
Small branches from the internal thoracic artery, known as medial mammary branches, supply the medial side of the mammary gland. The lateral side of the mammary gland is supplied by the lateral thoracic artery. The musculophrenic artery is a branch of the internal thoracic artery--it travels laterally and supplies blood to the 7th through 9th intercostal spaces. The posterior intercostal arteries are branches from the descending aorta--they supply the lateral and posterior portions of the intercostal space. The superior epigastric artery is a branch of the internal thoracic artery--it supplies the upper rectus abdominis muscle and the upper abdominal wall. The thoracoacromial artery supplies blood to the pectoral muscles, deltoid, subclavius, and the shoulder joint.