title: Anatomical characteristics of the accessory antero-lateral talar facet.
abstract: BACKGROUND
  We examined the anatomical features of the accessory antero-lateral talar facet (AALTF) in adults.
  
  
  METHODS
  The sample comprised 44 feet (male: 10 cadavers and 20 feet; female: 12 cadavers and 24 feet) obtained from 22 cadavers used for systemic autopsy. The mean age was 86.5 years. The talus and calcaneus were obtained from the autopsy cadavers, and the soft tissue was surgically removed from the bone. The talus and calcaneus were then separated and their anatomical features were observed.
  
  
  RESULTS
  The AALTF was identified in 11 of 44 (25 %) feet. The presence or absence of the AALTF and calcaneal facet opposing the AALTF were classified into four groups: (1) joint type with articular cartilage on both the talus and calcaneus; (2) talar type with articular cartilage on the talus only; (3) calcaneal type with articular cartilage on the calcaneus only; and (4) non-joint type with no articular cartilage on either the talus or calcaneus.
  
  
  CONCLUSIONS
  When the AALTF is present, the talus comes into contact with the calcaneus, and thus even slight changes around the talus and calcaneus can easily cause impingement.
authors.affiliation: Department of Orthopaedic Surgery, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae, Kawasaki, Kanagawa, 216-8511, Japan, takaaki.hirano@gmail.com.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Hirano
authors.forename: Hisateru
authors.initials: H
authors.lastname: Niki
authors.forename: Yui
authors.initials: Y
authors.lastname: Akiyama
authors.forename: Moroe
authors.initials: M
authors.lastname: Beppu
mesh_terms: D000328:Adult; D000369:Aged, 80 and over; D000843:Ankle Joint / Q000473:pathology*; D001837:Body Weights and Measures; D002102:Cadaver; D002111:Calcaneus / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D013628:Talus / Q000473:pathology*