title: The craniocervical venous system in relation to cerebral venous drainage.
abstract: OBJECTIVE
  Passing from the supine to the upright position favors cerebral venous outflow into vertebral venous systems rather than into the internal jugular veins. We sought to determine venous connections between dural venous sinuses of the posterior cranial fossa and craniocervical vertebral venous systems.
  
  
  METHODS
  Corrosion casts of the cranial and cervical venous system were obtained from 12 fresh human cadavers, and anatomic confirmation was made by dissection of three previously injected fresh human specimens. MR venography was performed to provide radiologic correlation.
  
  
  RESULTS
  The lateral, posterior, and anterior condylar veins and the mastoid and occipital emissary veins were found to represent the venous connections between the dural venous sinuses of the posterior cranial fossa and the vertebral venous systems. This study revealed the nearly constant presence of the anterior condylar confluent (ACC) located on the external orifice of the canal of the hypoglossal nerve. The ACC offered multiple connections with the dural venous sinuses of the posterior cranial fossa, the internal jugular vein, and the vertebral venous system. All these structures were shown by MR venography.
  
  
  CONCLUSIONS
  The lateral, posterior, and anterior condylar veins and the mastoid and occipital emissary veins connect the dural venous sinuses of the posterior cranial fossa with the vertebral venous systems. These connections are clinically relevant, because encephalic drainage occurs preferentially through the vertebral venous system in the upright position. The ACC is a constant anatomic structure that may play an important role in the redirection of cerebral blood in the craniocervical region.
authors.affiliation: Department of Radiology, Geneva University Hospital, 24 rue Micheli-du-Crest, 1211 Geneva 4, Switzerland.
authors.forename: Diego
authors.initials: D
authors.lastname: San Millán Ruíz
authors.forename: Philippe
authors.initials: P
authors.lastname: Gailloud
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Rüfenacht
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Delavelle
authors.forename: Frank
authors.initials: F
authors.lastname: Henry
authors.forename: Jean H D
authors.initials: JH
authors.lastname: Fasel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002550:Cerebral Veins / Q000033:anatomy & histology*; D002574:Cervical Vertebrae / Q000098:blood supply*; D016319:Corrosion Casting; D003388:Cranial Fossa, Posterior / Q000098:blood supply; D004388:Dura Mater / Q000098:blood supply; D005260:Female; D006801:Humans; D007601:Jugular Veins / Q000033:anatomy & histology; D008279:Magnetic Resonance Imaging; D008297:Male; D009333:Neck / Q000098:blood supply*; D011187:Posture; D014680:Veins / Q000033:anatomy & histology