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Myoclonus is a movement disorder characterized by involuntary, sudden, brief muscle jerks caused by muscular contraction (positive myoclonus) or inhibition (negative myoclonus).1,2 Myoclonus is generally a medical sign and not a diagnosis. It can occur in multiple disorders. A short differential diagnosis list includes anoxic brain injury, multiple sclerosis, Parkinson's disease, subacute sclerosing panencephalitis, and Creutzfeldt-Jakob disease. One way to classify the etiologies is through review of the clinical presentation and comorbid conditions. This article presents a review of anoxic brain injury related myoclonus. Post-anoxic myoclonus (PAM) can develop in either acute or chronic phase. Acute PAM occurs within hours after hypoxic event; chronic PAM (Lance-Adams syndrome) develops in survivors several days to weeks after the episodes of brain hypoxia.