Which arteries supply the ventral and medial portions of the pons and are implicated in the described infarct?

Arterial Supply to Ventral and Medial Pons in Pontine Infarction

The ventral and medial portions of the pons are supplied by penetrating arteries (perforating branches) arising directly from the basilar artery, which give rise to paramedian and anteromedial branches. 1

Primary Vascular Supply

The central and ventromedial pontine regions receive blood supply through a specific pattern of arterial branches:

• Perforating arteries from the basilar artery are the primary vessels involved, averaging 5.8 in number with a mean diameter of 0.39 mm 2
• These perforating vessels give rise to paramedian branches and anteromedial branches that supply the ventral and medial pons 2, 3
• The median branches (type 5 pontine arteries) penetrate the pons along the basilar sulcus and represent the most prevalent branch type supplying these regions 2

Vascular Border Zone Anatomy

Ischemic changes in the central pons occur along the transverse pontine fibers, which corresponds to a vascular border zone supplied by different penetrating arteries arising from the basilar and superior cerebellar arteries. 1 This anatomic arrangement explains why:

• Central pontine infarcts typically involve the central pontine white matter symmetrically 1
• These lesions differ from peripheral pontine lesions (such as those seen in multiple sclerosis) which are located at the periphery of the pons 1

Clinical Correlation with Infarct Patterns

The distribution of pontine infarcts directly reflects the underlying arterial anatomy:

• Anteromedial (paramedian) infarcts account for 73% of isolated pontine infarcts and result from occlusion of paramedian perforating branches 4
• These infarcts are strongly associated with basilar artery atherosclerosis (odds ratio 0.27 for lateral/posterior vs. anteromedial) 4
• Ventromedial pontine syndrome presents with severe hemiparesis, bilateral ataxia, and dysarthria due to involvement of these ventral and medial territories 5

Additional Contributing Vessels

While the basilar artery perforators are primary, supplementary supply may come from:

• The superior cerebellar artery (SCA) contributes to pontine blood supply in 2.5% of cases 2
• The anterior inferior cerebellar artery (AICA) participates in pontine perfusion in 12.5% of cases 2

This vascular anatomy is clinically significant because basilar artery branch disease is the most common cause of isolated pontine infarction (44% of cases), particularly associated with large ventral infarcts and progressive or fluctuating clinical courses. 5