Internal Carotid Artery

Move the cursor along the course of the internal carotid artery and its branches to identify individual segments.

Begins at the bifurcation of the Common Carotid Artery (level of C4).
Terminal branches: Anterior Cerebral and Middle Cerebral Arteries.
Four segments: cervical, petrous, cavernous, and supraclinoid
Move the cursor along the course of the internal carotid artery to identify individual segments.

Supraclinoid Segment
Internal Carotid Artery

Begins after penetration of dura, continues until bifurcation into Anterior and Middle Cerebral Arteries

Three Branches:
Ophthalmic Artery,
Posterior Communicating Artery, and Anterior Choroidal Artery.

Cavernous Segment
Internal Carotid Artery

Passes through cavernous sinus with Abducens Nerve.

Branches supply posterior pituitary (Meningohypophyseal Artery).

Petrous Segment
Internal Carotid Artery

Extends from base of skull to apex of petrous bone

Enters cranial vault via foramen lacerum.

Branches normally not seen angiographically - may be enlarged with carotid occlusive disease.

Cervical Segment
Internal Carotid Artery

Begins at the bifurcation of Common Carotid Artery (level of C4).

Extends to the base of the skull.

No branches normally seen.

Posterior Communicating Artery

Second branch of supraclinoid internal carotid.

Connects
anterior circulation (carotid system)
with posterior circulation (vertebrobasilar system)

Supplies thalamus, hypothalamus, optic chiasm, and mamillary bodies.

Common site for aneurysms.

Ophthalmic Artery

Usually arises intradurally (80-90%), below anterior clinoid process.

Supplies globe, orbit, frontal scalp, the frontal and ethmoidal sinuses.

Ophthalmic artery branches anastamose with Maxillary artery branches - potential for collateral flow in cases of proximal carotid occulsion.

Anterior Choroidal Artery

Last branch to originate from Internal Carotid Artery.

Cisternal segment: Artery passes through crural cistern, supplies optic tract, posterior limb of internal capsule, branches to midbrain,and lateral geniculate nucleus.

Plexal segment: Supplies choroid plexus of anterior portion of temporal horn of lateral ventricles.

Anterior Cerebral Artery

One of the terminal branches of internal carotid artery.

A1 Segment:
From Internal Carotid Bifurcation to Anterior Communicating Artery.

A1 Branches:
Medial Lenticulostriate Arteries (supply basal ganglia, anterior limb of internal capsule)
Recurrent Artery of Heubner (supplies head of caudate and anteroinferior internal capsule).

Infarction syndrome:
Medial Lenticulostirate Artery Contralateral impairment of motor function of face and arm

Middle Cerebral Artery

One of the terminal branches of internal carotid artery.

M1 (Horizontal) Segment: Branches:
Lateral Lenticulostriate Arteries (supply globus pallidus, putamen, internal capsule).

Infarction syndrome:
Lateral Lenticulostirate Arteries Contralateral hemiparesis and sensory deficits.
Speech (medial temoral lobe involvement) and visual function (Meyer's loop involvment) may also be compromised