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Right Vertebral Artery (Intracranial Part)

The right vertebral artery (intracranial segment, V4) is the continuation of the vertebral artery after it pierces the dura and enters the cranial cavity. It ascends through the foramen magnum, runs along the ventrolateral medulla, and joins its left counterpart at the pontomedullary junction to form the basilar artery. This segment gives off small branches supplying the medulla oblongata, spinal cord, and posterior inferior cerebellar artery (PICA).

The intracranial vertebral artery is surrounded by cerebrospinal fluid (CSF) in the subarachnoid space, which provides natural contrast on imaging. Accurate knowledge of its anatomy and imaging characteristics is critical for evaluating vertebrobasilar insufficiency, aneurysms, dissections, and posterior circulation strokes.

Function

  • Supplies blood to the posterior circulation including the brainstem, cerebellum, and spinal cord

  • Contributes to formation of the basilar artery, supporting posterior cerebral circulation

  • Gives off branches (e.g., PICA) supplying critical neurovascular structures

  • Maintains cerebral perfusion to vital autonomic and motor centers

Synonyms

  • Intracranial right vertebral artery

  • V4 segment of the vertebral artery

  • Cranial vertebral artery (right side)

MRI Appearance

T1-weighted images:

  • Intracranial vertebral artery appears as a flow void (signal loss) due to rapid blood flow, surrounded by CSF high signal

  • Vessel walls are not clearly visualized unless there is pathology (dissection, thrombus, or aneurysm)

T2-weighted images:

  • The artery continues to appear as a flow void (black lumen)

  • CSF remains hyperintense, providing excellent contrast

  • Pathological conditions like intramural hematoma or slow flow may produce high signal within the vessel wall or lumen

STIR (Short Tau Inversion Recovery):

  • Flow void persists; surrounding CSF and edema can be detected if there is brainstem or cerebellar infarction

  • Useful in evaluating arterial wall inflammation or perivascular edema

T1 Post-Contrast (Gadolinium-enhanced):

  • Normal intracranial vertebral artery enhances along the vessel wall, highlighting lumen patency

  • Pathological enhancement occurs with aneurysms, dissection, vessel wall inflammation, or thrombus

  • CTA/MRA correlation is often used for vascular mapping and surgical planning

CT Appearance:

  • On non-contrast CT, the intracranial vertebral artery is not clearly visible unless there is calcification or thrombosis

  • On CT angiography (CTA), the artery appears as a hyperdense, contrast-filled tubular structure, running along the ventrolateral medulla to join the basilar artery

  • Excellent for detecting dissections, stenosis, occlusions, aneurysms, and vessel variants

MRI images

Right Vertebral Artery (Intracranial Part) mri coronal image -img-00000-00000_00001

MRI images

Right vertebral artery (intracranial part)