Occipital artery anastomosis to vertebral artery causing pulsatile tinnitus.

Pulsatile tinnitus can result from various vascular etiologies that cause transmission of pulsatile turbulent flow into the inner ear. Less commonly, non-vascular sources cause increased blood flow and transmission of sound perceived as tinnitus. Thorough clinical examination leads to appropriate imaging evaluation and therapeutic planning. Most pulsatile tinnitus results from expected mechanisms, such as dural arteriovenous fistula, jugular bulb dehiscence, or paraganglioma; however, the literature contains reports of numerous rare causes, particularly variant anatomic morphologies. We present the case of a novel cause of pulsatile tinnitus in which collateral vascular flow compensated for decreased normal intracranial cerebral arterial supply and might have caused catastrophic consequences if intervened upon after assumptions based on an incomplete evaluation.