BACKGROUND There is currently no case described in the literature of epidural hematoma associated with subarachnoid hemorrhage due to dissection of a spontaneous radiculomedullary artery at the lumbar level and therefore its incidence and prevalence are not known. However, its etiology is thought to be similar and may not be diagnosed given its nonspecific symptomatology. OBSERVATIONS The authors present the case of an adult patient who consulted the emergency department for 2 weeks of low back pain. On physical examination there were negative signs of radiculopathy without neurological focalization. The patient was evaluated by neurosurgery via thoracic and lumbosacral spine magnetic resonance imaging, with findings of epidural hematoma associated with subarachnoid hemorrhage in the lumbosacral region. After that, panangiography was done. In the study, it was possible to visualize a dissection of the radicular artery at the L2 level. The patient was not a candidate for surgical management and continued with medical pain management. The patient has a good clinical evolution and was discharged. LESSONS The aim of the present case is to describe a unique case of radiculomedullary artery dissection as a cause of spontaneous epidural hematoma associated with a subarachnoid hemorrhage in the lumbar region.