The parapharyngeal vein-an accessory communication between the middle cerebral veins and the internal jugular vein: a case report.

Purpose: The superficial middle cerebral vein (SMCV) typically drains into the cavernous sinus, which, in turn, connects to the pterygoid venous plexus via a sphenoidal emissary vein. The latter may course through the foramen ovale. The pterygoid plexus drains in most cases into the retromandibular and facial veins. A peculiar SMCV drainage pathway to the internal jugular vein (IJV) via a parapharyngeal vein was found here.

Method: The anatomic variant reported here was identified by carefully reviewing the archived CT angiogram in a 68-year-old male case.

Results: A double SMCV was found on the right side. The resulting common SMCV trunk passed laterally to the foramen rotundum to empty into the cavernous sinus. A sphenoidal emissary vein joined it, which continued inferiorly through the foramen ovale to the pterygoid plexus. This plexus was connected to a reservoir on the inner side of the lateral pterygoid plate from which a fenestrated parapharyngeal vein left. It had two primary fenestrations, and the proximal one had a fenestrated arm. It reached inferiorly and turned around the external carotid artery. At that level, it received two tributaries: first, the superior thyroid vein and then, the facial vein. The resulting facial-parapharyngeal trunk ended in the IJV. These veins and the carotid arteries, deep to them, were hidden beneath the submandibular gland. The right maxillary vein and the anterior branch of the retromandibular vein were absent.

Conclusion: The parapharyngeal vein may be a direct drainage pathway for the SMCV and the pterygoid plexus. It should therefore be acknowledged and spared during various surgical approaches.