title: Geometry of Koch's triangle.
abstract: OBJECTIVE
  The first aim of this study was to determine the size of the Koch's triangle. The second one was to investigate relation between its dimensions and other individual-specific and heart-specific parameters as well as to create universal formula to estimate triangle dimensions based on these parameters.
  
  
  RESULTS
  This study is a prospective one, presenting 120 randomly selected autopsied hearts dissected from adult humans (Caucasian) of both sexes (31.7% females), with mean age of 49.3 ± 17.4 years. The length of triangle sides and angles were measured and the triangle area was calculated as well. Sixteen additional heart parameters were measured in order to analyse potential relationship between the dimensions of Koch's triangle and other dimensions of the heart, using linear regression analysis. The mean (±SD) length of the anterior edge was approximated to 18.0 ± 3.8 mm, the posterior edge to 20.3 ± 4.3 mm, and the basal edge to 18.5 ± 4.0 mm. The average values of the apex angle, the Eustachian angle, and the septal leaflet angle were 58.0 ± 14.4°, 53.8 ± 10.6°, and 67.6 ± 14.4°, respectively. The mean value of the Koch's triangle area was 151.5 ± 55.8 mm2. The 95th percentile of triangle's height (the distance from the apex to the coronary sinus) was 21.8 mm.
  
  
  CONCLUSIONS
  Mean values and proportions of triangle's sides and angles were presented. Koch's triangle showed considerable individual variations in size. The dimensions of the triangle were strongly independent from individual-specific and heart-specific morphometric parameters; however, the maximum triangle's height can be estimated as 22 mm.
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Kopernika 12, 31-034 Cracow, Poland.
authors.forename: Wieslawa
authors.initials: W
authors.lastname: Klimek-Piotrowska
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Kopernika 12, 31-034 Cracow, Poland.
authors.forename: Mateusz K
authors.initials: MK
authors.lastname: Holda
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Kopernika 12, 31-034 Cracow, Poland.
authors.forename: Mateusz
authors.initials: M
authors.lastname: Koziej
authors.affiliation: Department of Bioinformatics and Telemedicine, Jagiellonian University Medical College, Cracow, Poland.
authors.forename: Kinga
authors.initials: K
authors.lastname: Salapa
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Kopernika 12, 31-034 Cracow, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Piatek
authors.affiliation: Department of Anatomy, Jagiellonian University Medical College, Kopernika 12, 31-034 Cracow, Poland.
authors.forename: Jakub
authors.initials: J
authors.lastname: Holda
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks; D054087:Atrial Septum / Q000033:anatomy & histology*; D001344:Autopsy; D054326:Coronary Sinus / Q000033:anatomy & histology*; D004210:Dissection; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014261:Tricuspid Valve / Q000033:anatomy & histology*; D044465:White People
keywords: Atrioventricular node; Coronary sinus ostium; Eustachian ridge; Tendon of Todaro; Triangle of Koch