Vessel
Internal carotid artery
A major source of cerebral and orbital blood flow
High-yield
A usually branch-free cervical course distinguishes the ICA from the ECA. Intracranial branches include ophthalmic, posterior communicating and anterior choroidal vessels before the terminal ACA/MCA division.
Overview
The internal carotid ascends from the common-carotid bifurcation, normally without major neck branches. It passes through the petrous carotid canal and then the cavernous region before reaching the subarachnoid circulation. Its branches supply the eye and much of the cerebral hemispheres, and its communicating connections contribute to the circle of Willis.
Reference facts
- Origin
- Usually the common carotid bifurcation in the upper neck.
- Course
- Ascends in the carotid sheath, traverses the carotid canal, passes over the foramen-lacerum region and through the cavernous compartment, then crosses the distal dural ring into subarachnoid space.
- Branches
- Ophthalmic, posterior communicating, anterior choroidal and terminal anterior/middle cerebral arteries, plus smaller petrous, cavernous and hypophyseal branches.
- Supplies
- Large anterior cerebral territories, orbital structures including the eye, and smaller skull-base/pituitary territories; communicating variants can alter its cerebral distribution.
Clinical correlation
Carotid plaque can release emboli into retinal or cerebral arteries, causing transient visual loss or stroke. Severe narrowing can also reduce perfusion. These outcomes depend on embolic destination, collateral flow and the underlying disease.
Frequently asked questions
Where does the internal carotid artery originate?
Usually the common carotid bifurcation in the upper neck.
What does the internal carotid artery supply?
Large anterior cerebral territories, orbital structures including the eye, and smaller skull-base/pituitary territories; communicating variants can alter its cerebral distribution.
What are the branches of the internal carotid artery?
Ophthalmic, posterior communicating, anterior choroidal and terminal anterior/middle cerebral arteries, plus smaller petrous, cavernous and hypophyseal branches.
What is the course of the internal carotid artery?
Ascends in the carotid sheath, traverses the carotid canal, passes over the foramen-lacerum region and through the cavernous compartment, then crosses the distal dural ring into subarachnoid space.