title: Spinal nerve composition and innervation of the axillary nerve.
abstract: BACKGROUND
  The purpose of this study was to evaluate the spinal nerve composition of the axillary nerve and the contribution of each spinal nerve.
  
  
  METHODS
  Thirty brachial plexi extracted from Korean adults (15 men, 14 women, 1 unknown; left side, 13; right side, 17) were examined in this study.
  
  
  RESULTS
  The frequency of the contribution of C4 was 13.3%, and it was mainly innervated the deltoid and teres minor muscles. The frequency of inclusion of C7 was 20.0%. C7 fibers were mainly involved in the deltoid and cutaneous branches. The axillary nerve was primarily composed of fibers from C5 and C6 in 66.6%; C4, C5, and C6 in 13.3%; and C5, C6, and C7 in 20.0%.
  
  
  CONCLUSIONS
  These findings may be helpful to diagnose damage to axillary nerve structures that occur in such injuries as humerus fractures.
authors.affiliation: Department of Anatomy, Kwandong University College of Medicine, Naegok-Dong 522, Gangneung, 210-701, Korea.
authors.forename: Myong-Soo
authors.initials: MS
authors.lastname: Kang
authors.forename: Jung-Su
authors.initials: JS
authors.lastname: Woo
authors.forename: Mi-Sun
authors.initials: MS
authors.lastname: Hur
authors.forename: Kyu-Seok
authors.initials: KS
authors.lastname: Lee
mesh_terms: D000368:Aged; D001917:Brachial Plexus / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology
keywords: anatomy; axillary nerve; contribution of C4; innervations; participation of C7