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Pontine arteries

The pontine arteries are a group of small but crucial blood vessels that supply the pons—a key structure within the brainstem responsible for multiple vital neurological functions. These arteries branch from the basilar artery and run perpendicular to it, deeply penetrating and nourishing the central parts of the pons. Their integrity is essential for normal brainstem physiology, and their involvement in vascular pathology can have serious clinical consequences.

Synonyms:

  • Paramedian arteries (when referring specifically to the medial branches)

  • Pontine perforating arteries

  • Basilar perforators (less commonly used, but sometimes referenced in literature)

Origin:

  • The pontine arteries arise from the basilar artery.

  • They emerge along the entire length of the basilar artery, on its ventral (anterior) surface.

Course:

  • The arteries branch off nearly at right angles from the basilar artery.

  • They penetrate directly into the substance of the pons.

  • There are generally two main types:

    • Paramedian (medial) pontine arteries: Enter the pons close to the midline and supply medial regions.

    • Short circumferential arteries: Supply the anterolateral areas.

    • Long circumferential arteries: Pass laterally and dorsally to supply more lateral and posterior regions of the pons, including parts of the cerebellum.

  • The number of pontine arteries is variable, but they form a continuous series along the basilar artery’s length.

Function:

  • They supply blood to the pons, including:

    • The corticospinal and corticobulbar tracts.

    • The medial lemniscus.

    • The abducens nucleus and fibers.

    • The medial longitudinal fasciculus.

  • Any compromise (such as occlusion) can result in serious clinical syndromes (e.g., “locked-in syndrome”).

MRI Appearance:

  • Pontine arteries themselves are too small to be visualized directly on routine MRI.

  • High-resolution MRI (such as 3T or 7T TOF-MRA): May demonstrate flow voids or very tiny vessels along the ventral pons.

  • Infarction: Appears as areas of restricted diffusion (bright on DWI, dark on ADC) within the pons, usually paramedian.

  • Chronic ischemic changes: Can show up as T2/FLAIR hyperintensities in the regions supplied.

CT Appearance:

  • Like MRI, the pontine arteries are not directly visualized on standard non-contrast CT.

  • CT Angiography (CTA): May show small perforating arteries on high-resolution images, but still challenging.

  • Acute infarcts: Appear as subtle hypodensity in the pons, often paramedian in location, in later stages.

  • Hyperdense basilar artery sign (in thrombosis): May indirectly suggest involvement of pontine perforators.

MRI images

Pontine arteries coronal t2 mri image

CT images

Pontine arteries CT axial anatomy image -img-00001-00001