Head and neck anatomy left subclavian artery. The head and neck are emptied of blood by the subclavian vein and jugular vein. The brachiocephalic artery or trunk is the first and largest artery that branches to form the right common carotid artery and the right subclavian artery. This artery provides blood to the right upper chest, right arm, neck, and head, through a branch called right vertebral artery. The right and left vertebral artery feed into the basilar artery and upward to the Posterior cerebral artery, which provides most of the brain with oxygenated blood. The posterior cerebral artery and the posterior communicating artery
Smallest cardiac veins contribute to normal physiologic shunting of blood. As a consequence of the input of these vessels, blood in the left heart is less oxygenated than the blood found at the pulmonary capillary beds, albeit to a very small degree. The "openings of smallest cardiac veins" are located in the endocardium. Here the smallest cardiac veins return blood into the heart chambers from the capillary bed in the muscular cardiac wall, enabling a form of collateral circulation unique to the heart. Not every endocardial opening connects to the thebesian veins as some connect to the vessels of Wearn, which are arteries.