Arteries of the brain II (English)

The main artery of the anterior circulation of the brain is the internal carotid artery (ICA), which terminates as the anterior and middle cerebral arteries. The main artery of the posterior circulation is the vertebral artery. It enters the cranial cavity via the foramen magnum and gives off several branches which include meningeal branches, anterior and posterior spinal arteries, as well as the posterior inferior cerebellar artery. After this, the two vertebral arteries converge to form the basilar artery. This vessel courses vertically across the pons and posterior cranial fossa where it gives off several branches, namely the anterior inferior cerebellar, labyrinthine, pontine, mesencephalic and superior cerebellar arteries. The basilar artery terminates as a bifurcation which gives off the paired posterior cerebral arteries that contribute to the cerebral arterial circle (of Willis). The circle of Willis is an anastomotic loop/ring formed between four paired arteries and one unpaired artery which facilitates collateral blood between the anterior and posterior cerebral circulations as well as the right and left blood supply. Several small perforating (central) arteries emerge from the circle of Willis, many of which pass into the brain directly and supply the cortex and subcortical structures.