The neglected emissary vein in mastoidectomy; persistent petrosquamosal sinus in the laterally located sigmoid sinus

Abstract

The emissary veins are residual connections between intracranial venous sinuses and their extracranial drainage, which if not diagnosed preoperatively could be a cause of severe hemorrhage at the time of surgery which may be life threatening. The petrosquamosal emissary sinus (PSS) which is a rare embryonic emissary vein along the petrosquamosal fissure of the temporal bone connects dural sinuses with external jugular venous system. The PSS has been known to regress during fetal and early postnatal life. The imaging diagnosis of the PSS has been rarely reported in humans. We report the presence of the PSS with laterally located sigmoid sinus in patient with chronic otitis media. Our hope is that this report will be useful to the otologist during surgery.