INTRODUCTION : The emissary veins play a role in the extracranial venous drainage of the dural sinuses by connecting the internal and external venous network of the skull. The petrosquamosal sinus (PSS) is considered an emissary vein. The PSS is a well known yet rarely reported anatomical variant among the transmastoid emissary vein outlets. The incidence of persistent PSS is approximately 1% in routine CT examinations. We report two cases demonstrating this rare entity and describe its CT scan features.