Also known as “Wallenberg syndrome,” lateral medullary syndrome is a common brainstem stroke syndrome and is caused by ischemia of the dorsolateral medulla, which is nourished by the posterior inferior cerebellar artery (PICA), which comes off the vertebral artery. In the majority of cases, the culprit vessel is the vertebral artery itself causing artery-to-artery embolism. This vascular occlusion produces a wedge-shaped infarct in the dorso-lateral medulla, posterior to the inferior olivary nucleus. Though it was first described by Swiss physician Gaspard Vieusseux in 1808, it was later explained in more detail by German neurologist Adolf Wallenberg in 1895, whose name this syndrome still carries.