The vertebral artery then gives rise to the posterior inferior cerebellar artery, the largest branch of the vertebral artery and 1 of 3 arteries that supply the cerebellum.ДЄnother branch of the vertebral arteryВ is the single anterior spinal artery, which is supplied byВ bothВ vertebral arteries. Subsequently, at the level of the foramen magnum, the vertebral arteriesВ pierce the posterior atlantooccipital ligament, dura mater, and arachnoid membrane, reaching the subarachnoidal space. The vertebral arteriesВ arise from the subclavian arteries and proceedВ through the transverse foramina of the cervical vertebrae at the levels of C1 through C6. Vertebrobasilar circulation (posterior circulation) The ophthalmic artery is a branch of the ICA and supplies the eyes and parts of the paranasal sinus. The ICA supplies the frontal, parietal and the temporal lobes, as well as the diencephalon.

The direct continuations of the ICAВ are the middle cerebral arteryВ (MCA) and anterior cerebral artery (ACA).В The ACA is the smaller of the 2 andВ supplies the medial portion of the hemispheres to the parietal lobe.

The intracranial portionВ of the ICA isВ further divided into 5 segments (C1вЂ“C5), terms that are used in clinical practice. Each of these segments, with the exception of the pars cerebralis, has numerous branches. The ICAВ is divided into several segmentsВ including pars cervicalis (cervical segment), pars petrosa (petrous segment), pars cavernosa (cavernous segment), and pars cerebralis (cerebral segment). The internal carotid artery (ICA), on the other hand, has no branches in the cervicalВ region. The external carotid artery divides into 8 major branches. This site is referred to as the carotid bifurcationВ and contains the carotid body, which contains chemoreceptors that detect changes in the oxygen concentration and the pH-value of blood circulating through the carotid arteries. The common carotid arteryВ dividesВ at theВ level of the 4th cervical vertebra (C4) to form the ICA and external carotid artery. License: CC BY 4.0 AnatomyВ of the internal carotid artery (anterior circulation) Image: Arteries Supplying the Head and Neck.

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