title: The artery of Percheron revisited: a cadaveric anatomical study.
abstract: BACKGROUND
  The artery of Percheron (AOP) is a single thalamoperforating arterial trunk that provides bilateral supply to the paramedian thalami and the rostral midbrain. As this rare anatomical variant artery may be involved in endovascular procedures or encountered surgically during basilar terminus aneurysms, the present study was warranted.
  
  
  METHODS
  Thirty-four adult (20 male and 14 female) formalin-fixed cadaveric brains underwent dissection of the 68 posterior cerebral arteries. Observations were made of the presence and the variations of the thalamoperforating arteries as well as the presence of the AOP.
  
  
  RESULTS
  Thalamoperforating arteries arose from the superior or posterior surfaces of the P1 segment at a mean of a 1.87 mm (range, 0.39-5.25 mm) distance from the basilar apex and entered the brain through the posterior perforated substance. The average number was 4.25 (range 1-9), and the mean diameter was 0.73 mm (range 0.46-1.16 mm). Thalamoperforating arteries were classified into four different types according to their origin at the P1 segment: type I (bilateral multiple, n = 19), 55.8 %; type II (unilateral multiple, unilateral single, n = 4), 11.7 %; type III (bilateral single, n = 7), 20.5 %; type IV [one side with a single branch, the other side with no branches (the AOP), n = 4], 11.7 %. In three separate specimens with ruptured basilar artery aneurysms, the origin of the thalamoperforating arteries was incorporated not only into the posterior aspect of the aneurysm neck but also into the fundus.
  
  
  CONCLUSIONS
  In about one tenth of cases the possibility of the presence of a single arterial trunk that supplies the two paramedian thalamic territories should be taken into consideration during treatment planning of basilar terminus aneurysms. Furthermore, our data show that the thalamoperforating arteries may take off from both the aneurysm neck and the fundus.
authors.affiliation: Department of Neurosurgery, Uludağ University School of Medicine, Görükle Campus, 16059, Bursa, Turkey. hasankocaeli@yahoo.com
authors.forename: Hasan
authors.initials: H
authors.lastname: Kocaeli
authors.forename: Selçuk
authors.initials: S
authors.lastname: Yilmazlar
authors.forename: Turgut
authors.initials: T
authors.lastname: Kuytu
authors.forename: Ender
authors.initials: E
authors.lastname: Korfali
mesh_terms: D000328:Adult; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008636:Mesencephalon / Q000098:blood supply*; D020769:Posterior Cerebral Artery / Q000033:anatomy & histology* / Q000601:surgery; D012016:Reference Values; D013788:Thalamus / Q000098:blood supply*