Medial pontine branches of basilar artery

At a glance

English

Medial pontine branches of basilar artery

Latin (TA2)

Rami mediales pontis arteriae basilaris

System

Artery

Region

Head

Side

Paired, left and right

About the medial pontine branches of basilar artery

The medial pontine branches, also called paramedian pontine arteries, are a row of short, fine vessels leaving the posterior surface of the basilar artery along its length. The basilar artery lies in the midline groove on the front of the pons, so these branches pass straight backwards into the brainstem on either side of that groove.

Each runs deep into the pons close to the midline and ends near the floor of the fourth ventricle. Their territory is a wedge of tissue beside the midline that holds the descending corticospinal and corticobulbar fibres, the pontine nuclei among them, the medial lemniscus, and, at lower levels, the fibres of the abducens nerve and, further back, the medial longitudinal fasciculus. The lateral pontine branches serve the tissue on either side of this wedge.

These are end arteries, and disease of the small vessels or of the basilar artery wall at their mouths causes paramedian pontine infarcts. A small lesion often gives weakness of the opposite face, arm and leg, or slurred speech with a clumsy hand. Larger lesions add loss of position and vibration sense on the opposite side, or a same-side abducens palsy. When infarction affects both sides of the base of the pons, as in blockage of the basilar artery, the patient may be left awake but unable to move or speak except by moving the eyes vertically, the locked-in state.

Course and supply

Arises from

Posterior surface of the basilar artery along its course on the front of the pons.

Ends in

Pass backwards into the pons beside the midline, ending close to the floor of the fourth ventricle.

Supplies

Supply the paramedian pons: corticospinal and corticobulbar fibres, pontine nuclei, medial lemniscus and abducens fibres.