title: Surgical anatomy of the axillary nerve within the quadrangular space.
abstract: OBJECTIVE
  There is a paucity of literature regarding the surgical anatomy of the quadrangular space (QS), which is a potential site of entrapment for the axillary nerve. Muscle hypertrophy of this geometrical area and fascial bands within it have been implicated in compression of the axillary nerve.
  
  
  METHODS
  Fifteen human cadavers (30 sides) were dissected for this study. Measurements of the QS and its contents were made. The mean height of this space was 2.5 cm and the mean width 2.5 cm; its mean depth was 1.5 cm. The axillary nerve was always the most superior structure in the space, and in all cases the nerve and artery hugged the surgical neck of the humerus just superior to the origin of the lateral head of the triceps brachii muscle. This arrangement placed the axillary nerve in the upper lateral portion of the QS in all cadaveric specimens. The nerve branched into its muscular components within this space in 10 sides (33%) and posterior to it in 20 sides (66%). The cutaneous component of the axillary nerve branched from the main trunk of the nerve posterior to the QS in all specimens. Fascial bands were found in this space in 27 (90%) of 30 sides.
  
  
  CONCLUSIONS
  Knowledge of the anatomy of the QS may aid the surgeon who wishes to explore and decompress the axillary nerve within this geometrical confine.
authors.affiliation: Department of Cell Biology, University of Alabama at Birmingham, USA. rstubbs@uab.edu
authors.forename: R Shane
authors.initials: RS
authors.lastname: Tubbs
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Tyler-Kabara
authors.forename: Alan C
authors.initials: AC
authors.lastname: Aikens
authors.forename: Justin P
authors.initials: JP
authors.lastname: Martin
authors.forename: Leslie L
authors.initials: LL
authors.lastname: Weed
authors.forename: E George
authors.initials: EG
authors.lastname: Salter
authors.forename: W Jerry
authors.initials: WJ
authors.lastname: Oakes
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001132:Arm / Q000294:innervation; D001365:Axilla / Q000033:anatomy & histology* / Q000294:innervation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation; D010525:Peripheral Nerves / Q000033:anatomy & histology*; D012782:Shoulder / Q000294:innervation*