Atheromatous stenosis of the basilar artery (BA) can cause pontine infarctions by superimposed thrombosis, which occlude the BA itself or the orifices of the branches of the BA. Pontine infarctions can occur following large thromboembolism lodging at the BA lumen. Emboli usually lodge in the distal portion of the BA, occluding the superior cerebellar artery (SCA) or orifices of branches of the distal BA. Lipohyalinosis and branch atheromatous disease of the penetrating small arteries are the major vascular pathologies in most patients who develop pontine infarction. Pontine infarctions are caused by a variety of vascular pathologies that can develop in large brain-supplying arteries. About 10% of all brain hemorrhages occur in the pons. Before the development of computed tomography (CT) scanning, primary pontine hemorrhages (PPH) were considered a uniformly fatal disease characterized by horizontal gaze paresis, pinpoint pupils, high fever, quadriparesis, and rapid onset of coma.

Ataxia is the most important sign of cerebellar disease, but there are other potential causes of ataxia. Postural and limb tremor are additional signs of cerebellar disease. Patients with cerebellar disorders may walk with a wide-based, staggering gait, making it seem as if they were intoxicated by alcohol. Frontal lobe disorders might cause cerebellar-like symptoms with walking difficulties and clumsiness. Frontal lobe lesions are commonly associated with impairment of cognitive function and changes in personality, and often cause urinary incontinence. Lesions of the cerebellar hemisphere are followed by ipsilateral limb ataxia including hypotonia in acute lesions, and if the dentate nucleus is involved, kinetic tremor. Vascular lesions of the cerebellum itself and of the corticopontocerebellar and dentatothalamic pathways might result in ataxia. Limb ataxia and ataxia of gait are common in superior cerebellar artery (SCA), the posterior inferior cerebellar artery (PICA), and the anterior inferior cerebellar artery (AICA) territory infarctions.