title: New parameters describing morphological variations in the suprascapular notch region as potential predictors of suprascapular nerve entrapment.
abstract: BACKGROUND
  The suprascapular notch (SSN), bridged by the superior transverse scapular ligament (STSL), creates a pathway for the suprascapular nerve (SN). Morphological variations in the SSN region are common and can increase the risk of neuropathy by constricting the space for the nerve. The aim of this study was to establish new objective parameters that take this complex morphology into account.
  
  
  METHODS
  The SSN region of 100 formalin-fixed cadaveric shoulders was dissected. The dimensions of the SSN, the STSL and the anterior coracoscapular ligament (ACSL), as well as diameters of the SN, associated vessels and SN passage area, were measured by means of quantitative visual data analysis software to assign those structures to present classifications. The area reduction coefficient (ARC) and the ambit occupation coefficient (AOC) were defined and calculated for each shoulder.
  
  
  RESULTS
  The mean ARC and AOC for ligaments in the suprascapular region were: ARCSTSL = 71.6%, ARCACSL = 9.6%, AOCSTSL = 56.8% and AOCACSL = 9.1%. The SN passage area, ARC and AOC did not differ significantly between SSN types. The SN passage area and ARC differed significantly between band- and fan-shaped types of STSL. A significant relationship was observed between ARC and AOC (R=0.6855; p<0.0001). The SN passage area correlated significantly with ARC (R=-0.7555; p<0.0001) and AOC (R=-0.5609; p<0.0001).
  
  
  CONCLUSIONS
  The proposed parameters convey the complex morphology of the SSN region in a quantitative manner. The area reduction coefficient seems to be a more relevant indicator than the AOC as it better correlates with the SN passage area. Contrary to the SSN type, the STSL type significantly influences SN passage area and ARC.
authors.forename: Michał
authors.initials: M
authors.lastname: Podgórski
authors.forename: Mirosław
authors.initials: M
authors.lastname: Topol
authors.forename: Marcin
authors.initials: M
authors.lastname: Sibiński
authors.forename: Piotr
authors.initials: P
authors.lastname: Grzelak
authors.forename: Ludomir
authors.initials: L
authors.lastname: Stefańczyk
authors.affiliation: Department of Angiology, Chair of Anatomy, Medical University of Łódź, Narutowicza 60, Łódź 90-136, Poland. michal.polguj@umed.lodz.pl.
authors.forename: Michał
authors.initials: M
authors.lastname: Polguj
mesh_terms: D006801:Humans; D009408:Nerve Compression Syndromes / Q000473:pathology*; D010525:Peripheral Nerves / Q000473:pathology; D011237:Predictive Value of Tests; D012540:Scapula / Q000294:innervation* / Q000473:pathology*; D012782:Shoulder / Q000294:innervation* / Q000473:pathology*; D012785:Shoulder Joint / Q000294:innervation / Q000473:pathology