title: The superficial palmar arch and median artery as an example of misleading results due to a small number of investigated specimens or the use of different classifications.
abstract: BACKGROUND
  Small numbers of investigated specimens might lead to misinterpretations. Different classifications can change results dramatically. This is demonstrated by an investigation of the superficial palmar arch and the palmar median artery.
  
  
  METHODS
  A total of 702 upper limbs were investigated. Data were collected during eight dissection courses for advanced medical students and one workshop of hand surgery (number of investigated limbs per course between 52 and 111). The variations of superficial palmar arches were documented according to the classification of Lippert and Pabst as well as the occurrence of a palmar median artery. The results of each course were compared among each other, to the total result and compared to allocation according Jaschtschinski's classification.
  
  
  RESULTS
  In total, the results show complete arches in 52.15%. Incomplete arches with the ulnar artery supplying the thumb in 15.38%, reaching the index in 22.15% and the middle finger in 10.32%. Median arteries were documented in 4.5%. Individual course results varied concerning complete arches from 41.1% (37 out of 90) and 65% (35 out of 55), median arteries were found between 0 (0 of 69 hands) and 9.1% (5 of 55 hands). Classifying our total result with Jaschtschinski's classification there would have been complete arches in 67.8% (individual course result: 43.3-81.8%).
  
  
  CONCLUSIONS
  Small numbers of investigated specimens can lead to confounding results. The classification used has to be precisely determined. Both classifications need to be known to interpret results correctly. A repetition of investigation might be performed to confirm results.
authors.affiliation: Institute of Anatomy, Medical University Graz, Austria. georg.feigl@medunigraz.at
authors.forename: G C
authors.initials: GC
authors.lastname: Feigl
authors.forename: M
authors.initials: M
authors.lastname: Petrac
authors.forename: T
authors.initials: T
authors.lastname: Pixner
authors.forename: H
authors.initials: H
authors.lastname: Ulz
authors.forename: C
authors.initials: C
authors.lastname: Mörth
authors.forename: M
authors.initials: M
authors.lastname: Dreu
mesh_terms: D001158:Arteries / Q000033:anatomy & histology*; D002102:Cadaver; D006225:Hand / Q000033:anatomy & histology* / Q000098:blood supply*; D006801:Humans; D015203:Reproducibility of Results; D018401:Sample Size; D012680:Sensitivity and Specificity