Infarctions that occur in the brain stem which is comprised of the midbrain; pons; and medulla oblongata. There are several named syndromes characterized by their distinctive clinical manifestations and specific sites of ischemic injury. The disease is brain stem infarction (MONDO_0006686, a Monarch Disease Ontology entry). Also known as: brain infarction of brainstem, brainstem brain infarction, brainstem infarction.