title: [Anatomy and variants of the cerebral venous system--fact or defect?].
abstract: The anatomy of the cerebral venous system (CVS) is based on a known variable three-dimensional structure. For a correct recognition and characterization of its elements, a detailed knowledge of its anatomy and potential variants is essential. However, this structural changes, commonly named as variants, may appear in asymptomatic situations as well as associated to certain pathological syndromes with diagnostic and therapeutic consequences.
  
  
  OBJECTIVE
  The authors present a brief summary of the CVS anatomy, highlight the potential structural changes and discuss their ethiology as constitutional or pathological.
  
  
  RESULTS
  Based on clinical cases, the most frequent anatomical modifications will be presented and their ethiology discussed,whether constitutional or pathological.
  
  
  CONCLUSIONS
  The CVS is characterized by its various presentations. These changes are classically named as anatomic variants. However,they may appear associated to certain pathological situations. Only a profound recognition of the normal CVS anatomy allows a correct definition of the ethiology of the structural change as constitutional or pathologic.
authors.affiliation: Unidade Clínica Autónoma de Neurorradiologia, Hospital Prof. Dr. Fernando da Fonseca, Amadora, Portugal.
authors.forename: Leonor
authors.initials: L
authors.lastname: Rodrigues Lopes
authors.forename: Teresa
authors.initials: T
authors.lastname: Palma
authors.forename: Isabel
authors.initials: I
authors.lastname: Cravo
authors.forename: Cristina
authors.initials: C
authors.lastname: Gonçalves
authors.forename: Marco
authors.initials: M
authors.lastname: Bousende
authors.forename: João
authors.initials: J
authors.lastname: Martins Pisco
mesh_terms: D002550:Cerebral Veins / Q000002:abnormalities / Q000033:anatomy & histology*; D006801:Humans