title: Proatlantal intersegmental artery: a review of normal and pathological features.
abstract: OBJECTIVE
  Primitive carotid-vertebral and carotid-basilar anastomoses are formed early during human embryogenesis at approximately 24 days. From cephalic to caudal direction, these anastomoses are cranial extensions of the primitive internal carotid, trigeminal, otic, hypoglossal and proatlantal intersegmental arteries.
  
  
  METHODS
  Normal and/or abnormal morphofunctional aspects of prenatal and postnatal forms of the proatlantal intersegmental artery, from the 24th day of gestation to postnatal eight decades, are described according to personal and literature data. Many (ab) normal carotid-vertebral anastomoses are also marked in differential diagnosis of the proatlantal intersegmental artery.
  
  
  CONCLUSIONS
  The proatlantal intersegmental artery maintains the posterior circulation until the vertebral arteries are fully developed between the seventh and eighth gestational weeks. When this artery fails to obliterate, it becomes persistent one. The proatlantal intersegmental artery, most commonly, is an incidental finding or it may be of clinical significance in some patients.
authors.affiliation: Department of Anatomy, Faculty of Medicine, University of Nis, Blvd. Dr Zoran Dindić 81, 18000, Nis, Serbia. wassa@ptt.rs
authors.forename: Ljiljana
authors.initials: L
authors.lastname: Vasović
authors.forename: Marijola
authors.initials: M
authors.lastname: Mojsilović
authors.forename: Zlatibor
authors.initials: Z
authors.lastname: Andelković
authors.forename: Ivan
authors.initials: I
authors.lastname: Jovanović
authors.forename: Stojanka
authors.initials: S
authors.lastname: Arsić
authors.forename: Slobodan
authors.initials: S
authors.lastname: Vlajković
authors.forename: Zoran
authors.initials: Z
authors.lastname: Milenković
mesh_terms: D001158:Arteries / Q000002:abnormalities* / Q000196:embryology* / Q000473:pathology; D002339:Carotid Arteries / Q000002:abnormalities / Q000196:embryology; D002536:Cerebral Arteries / Q000002:abnormalities / Q000196:embryology; D002574:Cervical Vertebrae / Q000098:blood supply* / Q000473:pathology; D006801:Humans; D013116:Spinal Cord / Q000098:blood supply; D014711:Vertebral Artery / Q000002:abnormalities / Q000196:embryology / Q000473:pathology