title: Variable morphology of the anterior coracoscapular ligament - a proposal of classification.
abstract: BACKGROUND
  The suprascapular region is the most common site of compression and injury to the suprascapular nerve. This often results in suprascapular nerve entrapment, a possible risk factor being the anterior coracoscapular ligament (ACSL), a structure that runs in the suprascapular notch, below the superior transverse scapular ligament. The aim of the present study is to determine morphological variation of the ACSL and to measure the reduction in size of the suprascapular opening of specimens exhibiting it.
  
  
  METHODS
  A total of 84 human shoulders were included in the study. The following measurements were defined and performed for every ACSL: maximal length (ML), maximal proximal width (MPW) and maximal distal width (MPW). Additionally, two measurements of the suprascapular opening were collected: the area (aSSO) and the middle width (mwSSO). All of these measurements were taken using two independent methods: classical osteometry, and a new procedure based on the analysis of digital photographic documentation of the SSN taken using MultiScanBase v.14.02 software.
  
  
  RESULTS
  The anterior coracoscapular ligaments were present in 43 shoulders (51.2%). The analysis allowed the determination of four types of ACSL: first - fan-shaped (7%), second - band-shaped (62.8%), third - bifid (11.6%) and fourth - vestigial (18.6%). The mean area as well as the middle width of the suprascapular opening in the specimens with the anterior coracoscapular ligament was smaller than in those without this structure, however, no statistically significant differences were observed. The suprascapular nerve passed inferior to the ACSL in 2 specimens, and superior to it in 41.
  
  
  CONCLUSIONS
  The study presents a classification of the anterior coracoscapular ligament that has not been described in the literature and can be helpful in arthroscopic and open procedures of the suprascapular region. Knowledge of such anatomical variations confirms the safety of operative decompression to relieve entrapment of the suprascapular nerve.
authors.affiliation: Department of Angiology, Medical University of Łódź, Poland. michal.polguj@umed.lodz.pl
authors.forename: Michał
authors.initials: M
authors.lastname: Polguj
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Jędrzejewski
authors.forename: Mirosław
authors.initials: M
authors.lastname: Topol
mesh_terms: D002102:Cadaver; D003627:Data Interpretation, Statistical; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008023:Ligaments, Articular / Q000033:anatomy & histology* / Q000294:innervation; D012540:Scapula / Q000033:anatomy & histology* / Q000294:innervation; D012782:Shoulder / Q000033:anatomy & histology* / Q000294:innervation