The internal carotid artery (Latin: arteria carotis interna) is a major blood vessel in the head and neck region. It arises from the bifurcation of the common carotid artery.
The internal carotid artery arises at the level between the third and fourth cervical vertebrae. From its origin, the vessel passes up the neck in front of the transverse processes of the superior three cervical vertebrae, first lying lateral to the external carotid artery, then passing deeper and medially from it. The internal carotid artery enters the cranial cavity via the inferior aperture of the carotid canal in the petrous part of the temporal bone without giving off any branches. Here the artery turns anteriorly, passes through the cavernous sinus in the carotid groove, and exits it at the level of the anterior clinoid process. Then the internal carotid artery forms a small curvature upwards and then backward and divides into several branches.
The main branches of the internal carotid artery are the following:
The internal carotid artery on each side supplies the following regions: most of the cerebral hemisphere, the eye and its appendages, the forehead, as well as the external nose, nasal cavity, and paranasal sinuses.