Arteries of the head: Internal carotid artery (English)

The internal carotid artery (ICA) originates from the common carotid artery. It is usually divided into seven distinct parts based on its course and anatomical relations. This classification uses a numerical scale (C1-C7) based on the direction of blood flow, and describes the segments anatomically based on the compartments through which they travel. The ICA enters the skull via the carotid canal of the temporal bone. Segments C1, C3 and C5 usually do not have any branches, while small/variable may arise from segments C2 and C4. Segments C6/C7 provide several branches which supply the anterior circulation of the brain, as well as the orbit: the ophthalmic artery, superior hypophyseal artery, posterior communicating artery, anterior choroidal artery, anterior cerebral artery and middle cerebral artery.