Unique anastomosis between the condylar emissary vein and extracranial venous plexus: an anatomic and histologic case report

The condylar emissary vein traverses the condylar canal and connects the sigmoid sinus to the suboccipital venous plexus. Although the condylar emissary vein is a potential route for infection and metastasis, there exists a paucity of published studies on the anastomosis and histology of this vein. We present a variation observed during dissection of a 77-year-old, formalin-fixed female cadaver during a medical school anatomy course. Blunt and sharp dissections of the cervical spine, systematic measurements, histologic preparations of the vasculature, and a literature search were performed. The left condylar emissary vein directly connected the sigmoid sinus to the deep cervical vein with an additional anastomotic venous branch to the vertebral venous plexus. Histologic examination of the condylar emissary vein demonstrated arterialization of the vein with extensive elastic fibers permeating all layers. To our knowledge, this is the first study to describe the histology of the condylar emissary vein. Awareness of the histology of the condylar emissary vein and related extracranial anastomotic variations may be of use during neurosurgery of the suboccipital region. Furthermore, since the condylar emissary vein can serve as a route for metastatic spread of cancer, pathologists and radiologists couldalso benefit from awareness of its morphology.