title: Frequency, anatomical properties and innervation of axillary arch and its relation to the brachial plexus in human fetuses.
abstract: OBJECTIVE
  "Axillary Arch" (AA) is the main musculotendinous variation of the axillary region. The aim of this study was to reveal the frequency, anatomical properties, and innervation of AA and its relation with brachial plexus in human fetuses.
  
  
  METHODS
  In this study, 50 human fetuses (male: 20, female: 30), gestation age varied between 16 and 38 weeks (mean ± SD: 23.3 ± 5.3 week), were dissected at the anatomy laboratory of Mersin University, Faculty of Medicine.
  
  
  RESULTS
  AA was found in 11 of the 50 fetuses, and in 3 of 11, it was bilateral. Among both sides, 6 of 14 AAs were on the right and 8 were on the left side. Seven of AA's (7% of the specimens) were in muscular and 7 (7%) of them were in musculotendinous structure. With regard to Testut's classification, six (6%) of them were of complete type, six (6%) were incomplete and two (2%) were concordant with both types. Three different types of AA were defined considering the shapes of the arches. According to our classification, seven of the AAs were of type 1, two of them were of type 2 and five of them were of type 3. Additionally, the incidence of the T2 spinal nerve joining the brachial plexus was significantly higher in the specimens with AA (p = 0.001).
  
  
  CONCLUSIONS
  Each type of AA described in this study is thought to have individual clinical significance. Being aware of AA and its types can be important to determine a safe approach to the axillary region for surgeons. In addition, our results show the relation between the occurrence of AA and the variations in the formation of the proximal part of brachial plexus.
authors.affiliation: Department of Anatomy, Faculty of Medicine, Mersin University, Yenişehir Kampüsü, 33169, Mersin, Turkey. duzmansel@yahoo.com
authors.forename: Deniz
authors.initials: D
authors.lastname: Uzmansel
authors.forename: Zeliha
authors.initials: Z
authors.lastname: Kurtoğlu
authors.forename: Alev
authors.initials: A
authors.lastname: Kara
authors.forename: Nail Can
authors.initials: NC
authors.lastname: Oztürk
mesh_terms: D001365:Axilla / Q000196:embryology* / Q000294:innervation; D001917:Brachial Plexus / Q000196:embryology*; D005260:Female; D005333:Fetus / Q000294:innervation; D006801:Humans; D008297:Male