title: Novel classification of the posterior auricular artery based on angiographical appearance.
abstract: OBJECTIVE
  To investigate the length variation of the posterior auricular artery and propose a novel classification of the posterior auricular artery based on angiographical appearance.
  
  
  METHODS
  A series of 234 consecutive patients who had undergone conventional cerebral angiography was analyzed. The posterior auricular artery was examined on the lateral projection of the external carotid or common carotid arteriography. The posterior auricular artery was classified into four groups by length, using the external auditory canal and the top of the helix as radiographical landmarks. Our proposed classification is as follows: Type A, posterior auricular artery terminates between its origin and the center of the external auditory canal; Type B, posterior auricular artery terminates between the center of the external auditory canal and the top of the helix; Type C, posterior auricular artery terminates between the top of the helix and the vertex; and Type D, posterior auricular artery reaches up to the vertex.
  
  
  RESULTS
  A total of 424 (right, 214; left, 210) posterior auricular arteries were analyzed in 111 men and 123 women aged 11 to 91 years (mean, 61.0 years) examined for aneurysms in 78 cases, occlusive vascular diseases in 56, intracranial hemorrhages in 41, tumors in 35, and others in 24. Types A, B, C, and D were found in 15.1%, 34.9%, 48.8%, and 1.2% of the patients, respectively.
  
  
  CONCLUSIONS
  A novel classification of the posterior auricular artery identifies four types based on its length on cerebral angiography.
authors.affiliation: Department of Neurosurgery, Juntendo University Shizuoka Hospital, Izunokuni, Shizuoka, Japan.
authors.forename: Joji
authors.initials: J
authors.lastname: Tokugawa
authors.affiliation: Department of Radiology, Juntendo University Shizuoka Hospital, Izunokuni, Shizuoka, Japan.
authors.forename: Narisumi
authors.initials: N
authors.lastname: Cho
authors.affiliation: Department of Neurosurgery, Juntendo University Shizuoka Hospital, Izunokuni, Shizuoka, Japan.
authors.forename: Hiroharu
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Neurosurgery, Juntendo University Shizuoka Hospital, Izunokuni, Shizuoka, Japan.
authors.forename: Natsuki
authors.initials: N
authors.lastname: Sugiyama
authors.affiliation: Department of Neurosurgery, Juntendo University Shizuoka Hospital, Izunokuni, Shizuoka, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Akiyama
authors.affiliation: Department of Neurosurgery, Juntendo University Shizuoka Hospital, Izunokuni, Shizuoka, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Nakao
authors.affiliation: Department of Neurosurgery, Juntendo University Shizuoka Hospital, Izunokuni, Shizuoka, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Yamamoto
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017536:Carotid Artery, Common / Q000502:physiology*; D002533:Cerebral Angiography / Q000379:methods; D002648:Child; D004424:Ear Canal / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055815:Young Adult